The designers believe they've transferred all the emotion of a Porsche sports car to the Cayenne, but we'll leave that call to you. Tastes in styling are truly subjective. Many who examined the Cayenne during our test drive loved it. More than one interested observer said it resembles a frog. Either way, the stylist's handiwork has produced a 0.39 coefficient of drag, impressive for a big, boxy SUV, and good for limiting wind noise at high speed.

Cayenne is not a small vehicle. Measuring 188.3 inches in length, with a wheelbase of 112.4 inches, it's longer than the BMW X5 and Mercedes M-Class and a few hundred pounds heavier than both. Conversely, at 4949 pounds in its lightest specification, Cayenne weighs 550 pounds less than a Lincoln Navigator, which is two feet longer. An inspection underneath this SUV suggests that it's well engineered, perhaps over-engineered, compared to many mass-market sport-utilities. Apparently Porsche engineers preferred not to take chances with their first SUV, in the event that some owners actually drive it aggressively off road.

In size, Cayenne most closely matches Volkswagen's new Touareg; indeed, in some respects the Cayenne is a Touareg. That's because both were created from the same basic blueprint. These days ground-up vehicle development runs in the $1 billion range, and that puts a small company like Porsche (which sells 55,000 cars in a great year) at a distinct disadvantage, especially if it's venturing into new territory. Porsche had little choice but to find a partner, and it chose the Volkswagen-Audi Group, a company that has previously worked with Porsche on cars such as the 914 and 924.

Porsche was the project leader in the Cayenne/Touareg joint venture, and much of the work done on Volkswagen's dime was conducted by Porsche's contract engineering division, which accounts for a third of the company's business. Joint development was limited to the basic floor pan and some drivetrain components. Engines, suspension tuning, styling and all the finish work were the separate responsibility of each manufacturer.

As a result of this cooperation, Cayenne and Touareg bodies are built at a new plant in Bratislava, Czech Republic. Engines and other Cayenne components are built by Porsche in Zuffenhausen, Germany, and mated to the Cayenne shells at a new assembly plant in Leipzig, constructed exclusively for Cayenne with its own pavement and off-road test tracks.

This auto-industry backgrounder is relevant to any consumer preparing to part with a substantial amount of money for a high-end SUV because if two vehicles share a foundation, they're likely to share a basic quality, or lack thereof. A well-equipped VW Touareg will sell for about 40 percent of the price of a high-end Cayenne.

To Porsche's view, the Touareg is more utilitarian than Cayenne, and built for comfort. Cayenne has Porsche emotion, and it's built for speed. Porsche executives express confidence that, with the SUV's unique Porsche characteristics, consumers will easily recognize Cayenne as a special vehicle. We'd agree that some undetermined percentage of consumers would do exactly that.

Those "unique Porsche characteristics" include the engine. The Cayenne's 4.5-liter V8 has all the latest high-tech goodies, including Porsche's VarioCam variable valve timing, which allows an impressive combination of smooth idling, good low-end torque and free-revving high-end horsepower. The 4.5 also has a unique dry-sump lubrication system that allows uninterrupted oiling at extreme angles of operation, either off road or at high lateral gs on pavement. To account for higher operating pressures, the intercooled two-blower Turbo version has durability enhancements such as forged pistons and more oiling jets.

Power is transmitted through a permanent all-wheel-drive system with a variable-rate center differential managed by multiple clutch plates. This system is similar to that used on all-wheel-drive versions of the 911, with two Cayenne enhancements: a standard low range for real off-roading and a lock for the center differential. The drive system is controlled by Porsche's latest stability- and traction-managing electronics.

The standard Cayenne suspension uses coil-over struts with an extra set of conical springs to control lateral movement. The upgrade air suspension automatically adjusts ride height according to speed, with a range of nearly five inches. The air suspension also automatically (or manually) adjusts shock dampening rates for the preferred balance of ride quality and body-roll control. All Cayenne models feature Porsche Stability Management electronics, which intervene when the vehicles is driven to the limits of adhesion and help stabilize this SUV in the event of skidding at the front or rear wheels.

But what makes Cayenne a Porsche? So far, the equipment looks like standard fare on a lot of high-end SUVs. Well, Porsches are supposed to be powerful, and Cayenne certainly is. The normally aspirated 4.5-liter engine makes 340 horsepower at 6000 rpm and 310 pounds-feet of torque between 2500 and 5500 rpm, which puts it near the top of the SUV class. The Turbo generates a mighty 450 hp at 6000 rpm and 457 lbs.-ft. between 2250 and 4750 rpm, easily best in class. Judging by the seat of our pants, the Cayenne Turbo is easily the fastest SUV available (see Driving Impressions).

Beyond the power, there are more subtle things that say Porsche. The Cayenne's steering rack, for example, is supplied by ZF, a company that also builds the steering components for the 911. Cayenne is the first SUV with Y-rated tires (speed-rated for safe operation up to 186 mph) and the first with a six-speed automatic transmission (equipped with Tiptronic full-manual gear selection and steering-wheel shift buttons). Its brakes are truly impressive: 13.5-inch discs, with six-piston calipers in front and four-piston rear. Moreover, Porsche claims the Cayenne brakes were developed to meet the same rigid anti-fade standards as those on a 911.

Cayenne's all-wheel-drive system is also unique. Like similar systems, it can vary the amount of engine power distributed to the front and rear wheels, sending more or less power in one direction depending on available traction and other conditions. Yet in other luxury SUVs, the default torque distribution is as much as 70-percent front, 30-percent rear. In normal circumstances, this can make them drive a lot like a front-drive minivan. The Cayenne AWD has a default power split of 38-percent front, 62-percent rear, so the rear wheels clearly rule. This more closely replicates the rear-drive characteristics of a sports car.

Now we're back to styling, because the Cayenne's design does more than create a Porsche family resemblance. This sport-ute has near optimal front/rear weight distribution of 52/48 percent, for outstanding handling balance in all circumstances (the weight in most unladed SUVs is more heavily biased toward the front). At least as important, in Porsche's view, is the Cayenne's optimal aerodynamic balance. Aerodynamic downforce on the rear wheels increases with speed, delivering the high-speed stability that has become a Porsche trademark.