The 2015 BMW 428 is available as a 2-door, 4-seat coupe. Starting at $40,750, the 2015 BMW 428 RWD Coupe 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 35-mpg on the highway. The top of the line 2015BMW428w/SULEV AWD Convertible , priced at $ 50,750 , is powered by a 2.0L , 4 - cylinder engine mated to an automatic transmission that returns an EPA estimated 21-mpg in the city and 33-mpg on the highway.