The 2021 Audi A6 is available as a 4-door, 5-seat sedan. Starting at $54,900, the 2021 Audi A6 45 is powered by a 2.0L, 4-cylinder engine mated to an automatic transmission that returns an EPA estimated 23-mpg in the city and 31-mpg on the highway. The top of the line 2021 Audi A6 45 Sport, priced at $54,900, is powered by a 2.0L, 4-cylinder engine mated to an automatic transmission that returns an EPA estimated 23-mpg in the city and 31-mpg on the highway.