The 2005 Cadillac CTS is available as a 4-door, 5-seat sedan. Starting at $32,440, the 2005 Cadillac CTS w/1SB/1SC is powered by a 3.6L , 6 -cylinder engine mated to a manual transmission that returns an EPA estimated 17-mpg in the city and 27-mpg on the highway. The top of the line 2005CadillacCTSw/1SA , priced at $ 30,190 , is powered by a 2.8L , 6 - cylinder engine mated to a manual transmission that returns an EPA estimated 17-mpg in the city and 27-mpg on the highway.