The 2015 Lexus GS 350 is available as a 4-door, 5-seat sedan. Starting at $48,600, the 2015 Lexus GS 350 Base RWD is powered by a 3.5L , 6 -cylinder engine mated to an automatic transmission that returns an EPA estimated 19-mpg in the city and 29-mpg on the highway. The top of the line 2015LexusGS 350Crafted Line AWD , priced at $ 57,330 , is powered by a 3.5L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 19-mpg in the city and 26-mpg on the highway.