The 2008 Mercedes-Benz R-Class is available as a 4-door, 5-seat sport utility. Starting at $45,600, the 2008 Mercedes-Benz R-Class R 320 CDI AWD is powered by a 3.0L , 6 -cylinder engine mated to an automatic transmission that returns an EPA estimated 18-mpg in the city and 24-mpg on the highway. The top of the line 2008Mercedes-BenzR-ClassR 350 AWD , priced at $ 44,600 , is powered by a 3.5LL , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 15-mpg in the city and 19-mpg on the highway.