The 2008 GMC Envoy is available as a 4-door, 5-seat sport utility. Starting at $34,970, the 2008 GMC Envoy Denali 4x2 is powered by a 5.3L , 8 -cylinder engine mated to an automatic transmission that returns an EPA estimated 14-mpg in the city and 20-mpg on the highway. The top of the line 2008GMCEnvoySLT 4x4 , priced at $ 34,020 , is powered by a 4.2L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 14-mpg in the city and 20-mpg on the highway.