Audi revised its S6 in 2007 and adds only lane assist as a new option for 2008.

To create the S6, Audi started with an A6, then added Italian muscle up front, with a Lamborghini-sourced 5.2-liter V10 that produces 435-direct-injected horsepower. They then flow that power through a six-speed Tiptronic automatic transmission that offers manual shifting through steering-wheel paddles. From there the famed Audi quattro all-wheel-drive system takes over, but for the S6 it features a 40/60 rear wheel bias, which can apply up to 85% of engine power to the rear wheels when necessary, and a stiffer sports suspension with special 19-inch alloy wheels. Monstrous 15.2-inch rotors up front with 13-inchers in back assure swift, effortless braking. Audi claims 0-60 takes only 5.1 seconds. The EPA rates the S6 at 14/19 mpg city/highway.

And it's all very safe, at least according to the Insurance Institute for Highway Safety, which designated the S6 a Top Safety Pick for exceptional performance in frontal, side, and rear crashes. Audi provides the required front airbags, in addition to seat-mounted side-impact airbags up front and side curtain bags for the front and rear side windows. Antilock brakes with brake assist and an electronic stability system with traction control are also standard equipment.

The interior is the usual Audi paradise of luxury, style, and ergonomic efficiency. In the competition among the German performance titans, Audi always wins the interior wars. And although the S6 comes out as the only under-500-hp competitor in the contest with its peers - the BMW 5 series and the Mercedes-Benz E63 AMG - reviewers would pick the Audi for a cross-country drive.