The 2015 Audi RS 5 is available as a 2-door, 4-seat coupe. Starting at $70,900, the 2015 Audi RS 5 quattro Coupe 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 2015AudiRS 5quattro Cabriolet , priced at $ 79,200 , 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 22-mpg on the highway.