The 2010 Audi A8 is available as a 4-door, 5-seat sedan. Starting at $79,900, the 2010 Audi A8 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 2010 Audi A8 quattro Sedan, priced at $76,000, 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.