The 2009 Audi A8 is available as a 4-door, 5-seat sedan. Starting at $77,900, the 2009 Audi A8 L 4.2 quattro Long Wheelbase 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 2009AudiA8quattro Sedan , priced at $ 74,050 , 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.