The 2020 Audi S5 is available as a 2-door, 4-seat coupe. Starting at $51,900, the 2020 Audi S5 quattro Coupe is powered by a 3.0L , 6 -cylinder engine mated to an automatic transmission that returns an EPA estimated 20-mpg in the city and 27-mpg on the highway. The top of the line 2020AudiS5quattro Sportback , priced at $ 51,900 , is powered by a 3.0L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 20-mpg in the city and 27-mpg on the highway.