In launching its FX45, Infiniti invoked the image of a "bionic cheetah" (great speed and agility with superior mechanics and high technology) and floated the term S2UV (twice the Sport with all the Utility). The styling was described as a sports-car upper body fused to an SUV lower body. And it isn't just so much marketing-speak. Look at the thing, climb inside, start it up, and drive it around: The FX really is a curious amalgam of sport/utility architecture and performance-car flavor.

Fortunately, the FX45 drives sweetly enough to be a winner, especially if its unconventional lines appeal to you. A brief drive in Southern California turned up just one concern: The ride is stiff and busy--so much so that we worry how the FX will manage a Michigan diet of potholes and frost heaves. Otherwise, the FX45 is all Infiniti promised. It's quick (nothing wrong with 315 horsepower), stable, and responsive while also being roomy, comfortable, nicely appointed, and distinctive.

With its 4.5-liter V-8 and standard AWD, the FX45 squares off against the BMW X5 and Porsche Cayenne. There's also an FX35, with the 3.5-liter V-6 (tuned to 280 horsepower), offering a choice of rear- or all-wheel drive. The five-speed automatic transmission comes from the G35. Suspension is fully independent, with liberal use of aluminum components. The class' only 20-inch wheels (standard on V-8 models, available in a Sport Package with the V-6) were a styling priority right from the start, despite the ride penalty of their short-sidewall, 50-series tires.

Prices should start around $37,000 for a base 3.5 and $42,000 for a 4.5. Both models offer a Premium Package (sunroof, upgraded audio, and the like) and a Technology Package (intelligent cruise control, DVD player, tire-pressure monitor, and a nav system whose screen can display a rear-camera view for backing up). The V-6's Sport Package includes the 20s and firmer suspension, and, with the lighter engine in the nose, that one should be the agility champ.