The Cayenne model line now spans four variants: base, Tiptronic, S, and Turbo. The base Cayenne is powered by a narrow-angle, single-cylinder-head V6 producing 247 horsepower, and comes standard with full-time all-wheel drive with a high- and low-range. The Cayenne Tiptronic is identical to the base Cayenne, except that it's equipped with a six-speed automatic transmission with Porsche's Tiptronic manual shift mode. Cayenne and Cayenne Tiptronic both come standard with sophisticated traction management and skid-control electronics. The Cayenne S comes standard with a 4.5-liter dohc V8 engine mated to a Tiptronic automatic. The Turbo gets a twin-turbocharged version of the V8 and a whopping 450 horsepower.For 2005, the Porsche Cayenne has added useful standard equipment and introduced new option packages. Most significantly, it offers for the first time a 6-speed manual transmission.