The 2008 GMC Acadia is available as a 4-door, 7-seat sport utility. Starting at $30,140, the 2008 GMC Acadia SLE-1 FWD is powered by a 3.6L , 6 -cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 24-mpg on the highway. The top of the line 2008GMCAcadiaSLT-2 AWD w/4SB , priced at $ 38,665 , is powered by a 3.6L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 22-mpg on the highway.