The 2018 Audi A8 is available as a 4-door, 5-seat sedan. Starting at $82,500, the 2018 Audi A8 3.0T is powered by a 3.0L , 6 -cylinder engine mated to an automatic transmission that returns an EPA estimated 19-mpg in the city and 29-mpg on the highway. The top of the line 2018AudiA84.0T Sport , priced at $ 92,000 , is powered by a 4.0L , 8 - cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 26-mpg on the highway.