Power comes from an aluminum 5.2-liter, 40-valve V10 with dual overhead cams and direct injection. Also like the S6, the S8 uses a six-speed Tiptronic automatic transmission to push power to all four wheels through Audi's quattro all-wheel-drive system, a setup that incorporates front and rear locking differentials as well as a center Torsen limited-slip differential. However, unlike the S6, the 4,278-lb. S8 features the liberal use of aluminum, adds an extra two inches of wheelbase, and tacks on nearly six inches of overall length.