Porsche has produced the four-wheel-drive Carrera for decades, but only now has the German carmaker entered the full-time 4x4 SUV race (albeit to much grumbling from Porsche purists). It's already pulled ahead: The new Porsche Cayenne is the fastest SUV on the road. The S model ($55,900) goes from zero to 60 in seven seconds and has a top speed of 150 mph; the 450-horsepower Turbo ($88,900) does zero to 60 in five and a half seconds and tops out at 165. And their traction, stability, and suspension systems make them handle like a Boxster. In fact, the Cayenne has some Boxster blood in it. Designer Stephen Murkett has given the Turbo aggressive turbocharger bulges on the hood; the S model he's made race-car sleek. Inside both models are a 350-watt Bose sound system with 14 speakers, a navigation unit (optional in the S), and an elegant dashboard organized around a steering wheel shaped like a Ouija triangle. The Cayenne is built at a new factory near Leipzig with its own off-road course for customer test-drives. 800-767-7243; www.porsche.com.