The 2008 Audi A8 is available as a 4-door, 5-seat sedan. Starting at $70,690, the 2008 Audi A8 quattro Sedan is powered by a 4.2L , 8 -cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 23-mpg on the highway. The top of the line 2008AudiA8W12 quattro Long Wheelbase Sedan , priced at $ 120,100 , is powered by a 6.0L , 0 - cylinder engine mated to an automatic transmission that returns an EPA estimated 15-mpg in the city and 21-mpg on the highway.