The five-passenger A8 comes in three variations: the normal wheelbase 4.2, a long wheelbase 4.2, and a long wheelbase W12. The direct-injection 4.2-liter V8 produces 372 horsepower, which is routed to the ground by an eight-speed automatic Tiptronic transmission and quattro all-wheel drive. The W12 is a 6.3-liter twelve-cylinder engine with direct-injection and 500 horsepower. Optional tech features include a Bang & Olufsen sound system, solar-panel sunroof, dual-pane security glass, night vision, full LED headlights, blind spot, collision and lane assistance, and adaptive cruise control. Anti-lock brakes, electronic stability system, active head restraints, LED brakelights and ten airbags are some of the standard safety features on the A8. For 2012, the W12 engine returns to the line-up.