The 2008 BMW M3 is available as a 4-door, 5-seat sedan. Starting at $64,950, the 2008 BMW M3 Convertible is powered by a 4.0L , 8 -cylinder engine mated to a manual transmission that returns an EPA estimated 13-mpg in the city and 19-mpg on the highway. The top of the line 2008BMWM3Sedan , priced at $ 53,800 , is powered by a 4.0L , 8 - cylinder engine mated to a manual transmission that returns an EPA estimated 14-mpg in the city and 20-mpg on the highway.