The 2010 Audi S4 is available as a 4-door, 5-seat sedan. Starting at $45,900, the 2010 Audi S4 (M6) is powered by a 3.0L , 6 -cylinder engine mated to a manual transmission that returns an EPA estimated 18-mpg in the city and 27-mpg on the highway. The top of the line 2010AudiS4Base , priced at $ 47,300 , is powered by a 3.0L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 18-mpg in the city and 28-mpg on the highway.