Porsche's new Cayenne is the German sports-car maker's first-ever SUV, and also its first four-door, first five-seater, and the most powerful utility vehicle on the market when it does on sale later this year. A sibling to the new Volkswagen Touareg, the Cayenne S is powered by a 340-horsepower 4.5-liter V-8 mated to a sex-speed Tiptronic transmission. A twin-turbo version of the same engine delivers 450 horsepower and 458 pound-feet of torque. The latter model is said to sprint from 0 to 60 mph in less than 5.6 seconds, with a top speed of 166 mph. —Global Auto Net