One of my rules for covering the auto industry is to never judge a new car based on the manufacturer’s preview.

It is all too easy at these events to get swept up in an atmosphere of artificial excitement. You have been flown to some distant resort in California or Arizona in the middle of winter for a test drive. You are seeing a car for the first time, weeks before the general public. And you are surrounded by engineers, executives, and public relations operatives whose jobs depend on generating excitement for the vehicle at hand.

What car ever looks bad under these circumstances?

Last spring, I violated my own rule after driving the new Toyota Prius gas electric hybrid at a long-lead event in Napa Valley. I loved the car. For one thing, I was preconditioned to treat Toyota’s technical achievements with shock and awe. After I succeeded in hyper-miling the Prius to in excess of 70 miles per gallon, I was hooked. Talk of a $23,000 base price for the technological marvel was a bonus.

Well, six months later and I’m driving a Prius on my normal weekend test route. In the cold light of day, all those techno touches seem more curious than clever. The extreme aero shape of the body has left the instrument panel several feet away and made me feel as if I am driving from the middle of the car. The transmission shifter on the dash requires a re-education and some of the controls are bizarrely located (the seat heater switch is located down by my knee and completely out of sight).

That $23,000 starting price, meanwhile, has become a mirage. I have borrowed a car from one of the high trim level series, and the addition of the Advanced Technology Package (dynamic cruise control, pre-collision system, intelligent parking assist) has jacked the price up to $32,771.

After logging more than 200 miles on my normal test route, I was getting a smidgen over 50 miles per gallon – good but nowhere near my 70-plus mpg at the preview.

I have discovered I don’t really drive the Prius – I guide it. The combination of the awkward seating position, weird controls, pokey acceleration (zero to 60 in 9.8 seconds), and elongated aero shape makes me feel like I am traveling in a space capsule rather than riding in a car.

None of this is a knock on Toyota. It has created the world’s most popular – make that the world’s ONLY popular – gas electric hybrid, delivered on its fuel economy promise, and put it on sale at a reasonable price.

But it is a reminder to potential buyers that Prius is something special and doesn’t look, touch, or feel like a traditional gas-powered car.

And it is a reminder to me to never, never judge a car based on a manufacturer’s preview.

The supercar has been a struggle to sell, which means potential bargains for interested buyers.

Among the more exotic niches of the car business is the marketing of supercars.

The cars, which carry price tags in the mid-six figures, require a tricky marketing balance. If they become too scarce, speculators move in, driving up prices and making the cars unavailable to enthusiasts. But if too many examples show up on the market, they lose the appeal of scarcity and potential buyers move on to the next big thing.

Consider the case of Mercedes’s SLR McLaren. Based on its spec sheet, the car should have been a home run when it appeared in 2004. It had a supercharged V-8 engine that put out 617 horsepower and got the car from zero to 60 mph in 3.6 seconds; its top speed was 207 miles per hour. It sported an advanced carbon fiber body and retro scissor-style doors. The SLR also had a history behind it. It was said to have been inspired by the Mercedes 300 SLR of 1955.

But the market for supercars was weakening when the SLR came out, and the car received some middling reviews. There were complaints about its styling and its function — whether it was really a sports car or a grand tourer in disguise. Mercedes had planned to sell 500 SLRs a year at $495,000 each, but after 2005, it wasn’t able to achieve that goal. It ended production of the car in 2009 — two years ahead of schedule.

Today, the SLR is unloved and unwanted. According to one dealer, there are currently 26 unsold cars at the port in Los Angeles. Based on last year’s selling rate, that would be a three-month supply. A Mercedes spokesperson says that number is too high — she says “only a handful of SLRs are there” (though there may be more in East Coast ports).

If you want to buy an SLR for Christmas, now is the time for a bargain. Mercedes says that if you group all the wholesale and retail dealer allowances together, you could knock the price down by $175,000. A dealer says the number is actually higher: $250,000 off the sticker.

But if you think the SLR has become damaged goods, never fear: a new Mercedes supercar is on the way. The 2011 SLS AMG, introduced at the Frankfurt Motor Show in September, gets a 571 horsepower V-8 that will fling the car to 62 mph in 3.8 seconds, with a top speed of 197 miles per hour. In addition, it has genuine butterfly doors. The estimated price is $225,000 or less than half the price of the SLR.

Caveat emptor.

Are better times coming? Ford seems to think so, based on the design and features of the new Lincoln MKT.

When you want to take the psychic temperature of the Ford Motor Co., all you have to do is look at the latest offerings from Lincoln.

When times are tough, the company makes little effort to distinguish luxury-pretender Lincoln from its homelier Ford origins. A new grille here, redesigned tail lamps there, and you have summarized the major differences between, say, the Ford Edge and Lincoln MKX.

But when better times are coming, Ford digs deeper into its product development budget to more fully differentiate Lincoln and add more luxury features.

Cue the 2010 MKT. While it’s based on the utilitarian Ford Flex people-mover, the MKT looks nothing like it, with a new body panels and unique design flourishes like the upswept kink in the rear fenders. For proof, park the MKT in your driveway and you won’t find anybody whispering “poor relation.” At 17 ¼ feet long and weighing nearly 5,000 pounds, MKT is an imposing piece of automotive iron — half a foot longer and 350 pounds heavier than the Flex.

Evaluating design is a subjective matter. I like the MKT’s split waterfall grille, but found the tailgate-wide rear insignia/taillight treatment a bit extravagant.

Inside, the interior is a masterful combination of luxury and utility, marred only by retro-styled instruments that are hard to read. And watch out for the Collision Warning with Brake Support system. Pull up too close to the car in front of you and a dozen LED lights start flashing in the windshield while the radio signal is damped and alarms blare. You’d think you were at Three Mile Island during a meltdown.

Reviewers have praised the performance of the MKT — and with good reason. The optional EcoBoost V-6 engine with twin turbochargers lights up quickly with the push of a button and gets the car underway so smoothly you would swear you are driving a V-8. Another plus: There is no turbo lag and no turbo whine. An additional EcoBoost payoff comes from fuel economy: The MKT with all-wheel-drive gets 16 mpg city/22 mpg highway, about the same as a Flex AWD with a standard V-6 that produces only 265 hp. I confirmed the highway figure during a 100-mile run.

All that technology, performance, and carrying capacity for seven carries a significant price tag. The MKT’s base price is $49,995 (including delivery), making it the second most expensive vehicle in the Lincoln lineup after the Navigator. My optioned-up test vehicle was listed at a stiff $57,180.

At least you likely won’t see yourself coming and going. Lincoln is still a low-volume brand and Edmund’s reports that MKT sales are off to a slow start.

Yet it is good to see Lincoln acting like a real luxury car contender, and better still to know that Ford sees bluer skies ahead.

Let’s get it out of the way right at the top: The new convertible version of Aston’s V-12 powered 2+2 grand tourer (with automatic transmission) carries a sticker price of $285,990.

That’s crazy, right, as we struggle to emerge from the worst economic downturn since the Great Depression?

But let’s consider this: The DBS Volante is the most drop-dead gorgeous, most satisfying car I can ever remember driving.

More refined and sophisticated in appearance than a typical Italian supercar, yet more expressive than a Porsche or a Jaguar, the Aston is stunning to look at. Every detail, from the four mesh inserts in the hood and the flared headlamp openings to the carbon fiber door handles is executed with an extra helping of panache that elevates it from the merely attractive to the alluring.

My test car glowed in a hue that Aston endearingly describes as Hardly Green that was both unique and eye-catching, and worked nicely with the brown leather surface coverings.

The view from behind the wheel is no less stunning. The winged Aston emblem dominates the steering wheel, the instruments are finely calibrated, and the Bang and Olufsen audio provides superb fidelity.

Fire up the six-liter engine by inserting the ignition device in its slot, and the Aston barks to life. Onlookers snap to attention. Select a gear by punching one of the traditional Aston dashboard buttons and you are off.

Power arrives smoothly and you can feel the six-speed transmission shifting smoothly up and down through the gears, proceeding so smartly that manual gear changes would be an insult to the software.

My agreement with Aston prohibited me from performance tests like 0-60 acceleration, so I can only report the company’s claim that 62 miles per hour can be reached in 4.3 seconds and top speed is 191 miles per hour.

As for flaws, I can identify but two: The carbon fiber chin spoiler is so close to the ground that it inhibits travel over rough surfaces, and the trunk is too tight to accept a bag of golf clubs.

But practicality isn’t the point here. Like a fine watch, the DBS Volante represents an ambitious expression of the mechanical arts.

For those who can afford to indulge such pleasures, and who can accommodate a Volante in their fleet of automobiles, it is an entirely worthy addition.

I would consider it a modern-day classic, for which paying the unreal sticker price is merely part of the pleasure of ownership.

The red-over-black GT-R squatted in my driveway like an angry beast from another planet. No graceful shapes or elegant curves disguised its blunt purposefulness.  This is the car designed, first and foremost, to beat all other production models around Germany’s famed Nürburgring.  Whether it does or not, it lives up to its nickname “Godzilla” even when parked.

Which would be fine, except that I live in northwestern Connecticut, and, despite the proximity of Lime Rock Park (“Roadracing capital of the East”), I almost never get an opportunity to evaluate the full potential of a 480-horsepower car that can claw its way to 60 miles an hour in 3.9 seconds (without launch control) and claims a top speed of 195 miles per hour.

What I could do was make some short loops around town and then log 150 miles at higher speeds on the Massachusetts Turnpike. What I found was that this is not a car you would choose to make a leisurely morning run for the New York Times and a cup of coffee.  That’s mainly because first gear in an all-wheel-drive car with the power of the GT-R has all the subtlety of a stump-pulling tractor, heaving and jerking as it translates the immense horsepower into forward motion.  Second gear in the dual clutch, paddle-shift, six-speed transmission was lots smoother,  but you needed to get up a little speed before the computer brain behind it would allow you to get there.

Nor does the view from the driver’s seat give you much to warm up to.  The cockpit has all the ambiance of an F1 racer, with surfaces and instruments designed more for practicality than esthetics, purpose  not pleasure. This is not a car for lounging in.  One thoughtful touch is the addition of two rear seats, suitable for pets, small children, and masochistic adults – an unusual  concession to practicality.

But although the GT-R is designed to be a daily driver and carries a relatively modest sticker price of $72,000, it is as finicky in some ways as an exotic.  Specifically, the alignment tolerances are so narrow that a minor irregularity can throw the wheels out of whack.  My GT-R shimmied regardless of the road surface, requiring constant corrections of the steering wheel.  I was informed that it needed a wheel alignment after only a few thousand miles of use.

With those caveats, the GT-R lived up to its advance billing as one of the most technologically-advanced,  high-performance cars in the world and is ably performing its task of raising Nissan’s profile. GT-R owners form a very exclusive club – the purchase of only 321 cars was transacted in November, but enthusiasts have gone bonkers over it and Motor Trend voted it car of the year. For me, however, the GT-R is a car more to admire than to love.

A two-seat convertible like the 911 Turbo Cabrio that accelerates to 60 miles per hour in four seconds and carries a sticker price of $154,050 would seem like an irrelevance in these days of $4 gasoline and difficult economic times.

Porsche 911 Turbo Cabriolet

It is – except to two important constituencies: Porsche and its customers. Against all logic, the 911 line of rear-engine sports cars continue to be the most popular Porsches, outselling the less-expensive Boxster two-to-one. As the most expensive 911, the Turbo Cabrio thus becomes the flagship of the Porsche brand and an aspirational target for its buyers. If you are dying to have a Porsche, you might as well pop for the top of the line.

The “arctic silver metallic” car I drove recently effortlessly satisfield both parties. It is one of the most strikingly handsome cars on the road, with a tailored front-end, bulging rear flanks, and tasteful spoiler far more refined than those on earlier turbo models. The descriptive “whale tail” no longer applies. Inside, the black full-leather interior was purposeful, rather than indulgent, and Porsche is making strides by improving the appearance and utility of its interior controls (though you would never mistake them for a Lexus). The one-touch convertible top, which stows neatly in the rear deck, operates efficiently and unobtrusively.

The big surprise comes when you get behind the wheel, because the Turbo Cabrio is as comfortable as a well-worn leather glove. It is one of those rare super cars that is equally at home running errands as it is accelerating through the gears. The pedals operate easily, the shifter on the manual gearbox is a model of balance and performance, and the steering wheel responds to the most subtle of inputs. Once you get used to finding the ignition switch on the left hand side of the steering wheel (for those running Le Mans starts), it functions effortlessly as a daily driver. And at 15 miles per gallon city, 24 mph highway, the mileage isn’t horrible.

With its 480-horsepower engine revving at full throttle, the Turbo Cabrio is capable of scary high speeds, but you won’t find an analysis of its top-gun handling characteristics here. Absent hot laps on a race course or avoiding the police on some deserted highway, the Turbo Cabrio possesses performance capabilities that will be infrequently accessed by its owners. But that doesn’t prevent Porsche from charging top dollar for the car – or from its owners paying it. Both parties can feel they have exchanged fair value.

BMW 128i

Sometimes the obvious needs to be re-examined. That became clear to me the other day when I looked at the sticker prices of two vehicles I was driving. The two were radically different in size, function, performance, and status. Yet their as-tested prices came within $1,000 of each other.

For the enthusiast, the price similarity is irrelevant. He buys cars that turn him on, and the monetary value they represent is secondary. Not so the average consumer. Image and performance are important buying considerations, but function and cost are probably top his concerns.

So warning: I’m comparing apples and oranges here, but the analysis may be informative –- and entertaining.

2009 Ford Flex

In this corner is the 2008 BMW 128i Coupe, BMW’s new “entry level” model that sneaks into the lineup below the 3 series. Except for Mercedes (DAI), probably no other manufacturer in the world would consider the 128 entry level. The coupe seats two adults comfortably, four in a pinch, and is styled to resemble its larger BMW cousins. It is powered by the same dual overhead cam, 24-valve, 6-cylinder engine as the 3 series, and is available with a load of exotic equipment — iPod adapter, HD radio, rain sensor. The standard features contributed to a base price of $28,600 and the additional goodies push the as-tested price to $42,396.

In the other corner is the 2009 Ford Flex which, depending on your viewpoint, reinterprets the station wagon, minivan or sport utility vehicle. Some two-and-a-half feet longer than the 1-series, it seats seven people in three rows of seats. Its most notable styling feature is a flat roof, available in a contrasting color that makes the Flex look even longer than it is. Although a Ford, the base price on the all-wheel-drive Flex is a not-insubstantial $36,555 and adding some gotta-have extras -– rear back-up camera, dual-aperture sun roof -– jacked the sticker on my test vehicle up to $43,250.

The Flex is more maneuverable than it looks. Its 3.5L DuratecV-6, introduced in 2006, puts out 265 horsepower; the steering is responsive; and maneuverability is adequate.  But this is still a big vehicle that nobody is going to take joyriding. I got nearly 21 miles per gallon in highway driving with a couple of passengers on board, but more aggressive drivers report in at a less-admirable 15 mpg.

Not surprisingly, the BMW was the favorite for short, single-driver trips. Quick and agile, it was highly entertaining and encouraged recreational driving. The EPA estimates fuel economy at 19 mpg city, 28 highway. But its size limits its utility and its stiff price may make you wish you had popped for the larger 3 series instead. (The four-door 328i’s start at $32,700).  Quite visibly, the Flex offered more car for the money, and I liked its bright, well-tailored interior –- one of the nicest I’ve seen. Still, the Flex is too much car most of the time, except for big families or those with heavy car-pooling duties. I’d find a five-seat Flex easier to live with.

So what does my analysis prove? One, there is a big universe of vehicles out there. Two, they don’t come priced by the yard –- or by the pound. And three, they probably cost more than you think. Luckily, with sales in a recession, it is a buyer’s market for whatever size you are shopping for.

Launches are a huge deal in the auto business. If the right message does not get out when a new model goes on sale, there is seldom a second chance.

Nobody understands that better than Infiniti, Nissan’s luxury brand (NSANY). The brand launched in the shadow of Toyota’s Lexus (TM) in 1989 with an ill-conceived “rocks and trees” advertising campaign and never really recovered. Today, Lexus is the most popular luxury brand in the United States, while Infiniti sells less than half as many vehicles. So low is Infiniti’s public profile that it discontinued its Q45 flagship a year ago — and nobody noticed.

The 2009 FX50 won’t boost Infiniti’s sales figures much – only 134 units of its predecessor model, the FX45, have been sold through May — but it should raise its visibility. It is truly exotic in its conception and execution; in many ways it is the most  revolutionary mass-production vehicle of past five years. When former BMW CEO Helmut Panke went searching for new ideas for the German car company, he often cited the FX as a source of inspiration.

Think of the FX as the Toontown version of the modern station wagon: it has seating for four, with storage space behind the back seat, and a low roof with a barely functional roof rack on top. The cartoon inspiration comes from the proportions: An exaggeratedly long nose coupled to a passenger compartment that, instead of being squared off at the rear, is tucked into a dramatically-bobbed tail. The FX has perhaps the shortest rear overhang of any car on the road – its curved shape is reminiscent of some classic French cars from the 1930s. Completing the effect are some baroque styling elements – extreme cat’s eye headlamps, open-mouthed grill, Wurlitzer-inspired fender vents – and the absurdly oversized wheels.

Under the skin, the FX50 is a rolling test-bed of technology.  Two of the highlights are the around-view monitor, introduced a year ago, which gives a 360-degree view around the car from four cameras, and lane departure prevention.  While other Infinitis merely send out beeps to warn the driver when he strays out of a lane, the FX50 gently applies its brakes to nudge him back in.

During more than 200 miles of driving this extroverted vehicle, all that technology took some getting used to. When I pulled out to pass, for instance, the lane departure prevention system momentarily tried to hold me back. But I immediately warmed to the more traditional elements of the car — the seats, controls, and interior appointments — which were executed with uncommon skill.

There is a price to be paid for all of this, of course, and it’s steep: a base price of $56,700 plus a $815 destination charge; $69,145 with many bells and whistles. Should you decide to buy one, plan on spending a lot of time explaining to yourself and others why you did. Unlike a vehicle in a more conventional package that carries a recognizable brand, the Infiniti FX50 doesn’t make a predictable statement about itself or its owner.  And therein lies its charm.