The 2018 Audi S3 is available as a 4-door, 5-seat sedan. Starting at $43,650, the 2018 Audi S3 2.0T Premium Plus is powered by a 2.0L , 4 -cylinder engine mated to an automatic transmission that returns an EPA estimated 22-mpg in the city and 28-mpg on the highway. The top of the line 2018AudiS3Tech , priced at $ 45,550 , is powered by a 2.0L , 4 - cylinder engine mated to an automatic transmission that returns an EPA estimated 22-mpg in the city and 28-mpg on the highway.