Among the rarefied ranks of the biggest and most luxurious sedans, models such as the BMW 7-Series, Mercedes S-Class, and Lexus LS400 rule.
Audi's all-wheel-drive flagship A8 tries to compete, and has some unique features.
For example, the A8 has an all-aluminum body and all-wheel-drive.
A five-speed automatic transmission is standard equipment.
The A8 has the usual air bags in front, plus one in each of the four doors.