Audi's luxury flagship slides into the dimensional gap between a BMW 7-Series and the smaller Mercedes-Benz E-Class. Use of aluminum for most frame and body panels, however, means the A8 weighs 300 to 500 pounds less than comparable luxury sedans. As its numerical designation suggests, a 3.7-liter aluminum V8 engine powered the A8 3.7 sedan, which came with front-wheel drive and standard traction control. A 300-horsepower, 4.2-liter V8 went into the A8 4.2, along with Audi's permanently engaged Quattro all-wheel-drive system. Quattro automatically sends power to the wheels with the most traction in slippery conditions. Both models were equipped with six airbags: dual cushions in front, plus smaller airbags in each of the four doors. Rear side airbags were claimed to be an industry "first." Standard equipment also included antilock braking, an antitheft system, and 5-speed automatic transmission. Each A8 sedan also got a power tilt/telescoping steering wheel, power sunroof, cruise control, keyless entry, leather upholstery, and wood interior trim.Three option packages were available. The Cold Weather group featured heated steering wheel and front/rear seats, plus a ski sack. The Warm Weather option included insulated glass and sunshades for the back window and rear side windows. A solar sunroof in that group included interior fans that engaged when the car was parked in the sun. Rivals included the BMW 7-Series, Lexus LS 400, and Mercedes-Benz E-Class.