Yet the A8 remains fresh. Its clean, elegant profile emphasizes the large wheel arches and massive aluminum wheels. Audi has mastered the art of producing sedans that are striking -- imposing, even - without being overbearing. Optional 17-inch wheels add to its aggressive but understated appearance.

Underneath the A8's aluminum body is the Audi Space Frame. Developed with Alcoa, the patented space frame is manufactured with seven different aluminum alloys. It has fewer parts (and joints) than the typical steel unibody, it's more rigid, and it's 40-percent lighter than a steel frame. Furthermore, aluminum's increased energy-absorbing capabilities helped the A8 become the only member of the premium luxury class to earn the National Highway Traffic Safety Administration's dual five-star safety rating.

A8 was the first automobile with dual front airbags and side-protection airbags for both front and rear passengers. The current system also includes Sideguard airbags that discharge from the roof lining and help cover side window area in an impact.

At 310 horsepower, the A8's 4.2-liter V8 has a slight edge over the BMW 740i and Mercedes-Benz S430. Yet, thanks to the engine's efficiency and the Audi's lighter weight, the A8 has no gas-guzzler tax on its window sticker.