The 2008 Cadillac STS is available as a 4-door, 5-seat sedan. Starting at $43,775, the 2008 Cadillac STS V6 RWD is powered by a 3.6L, 6-cylinder engine mated to an automatic transmission that returns an EPA estimated 17-mpg in the city and 26-mpg on the highway. The top of the line 2008 Cadillac STS V8 AWD, priced at $54,825, is powered by a 4.6L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated 14-mpg in the city and 21-mpg on the highway.