The 2016 Cadillac CT6 is available as a 4-door, 5-seat sedan. Starting at $55,495, the 2016 Cadillac CT6 3.6L Standard AWD is powered by a 3.6L , 6 -cylinder engine that returns an EPA estimated 18-mpg in the city and 27-mpg on the highway. The top of the line 2016CadillacCT63.0L Twin Turbo Platinum AWD , priced at $ 87,465 , is powered by a 3.0L , 6 - cylinder engine that returns an EPA estimated 18-mpg in the city and 26-mpg on the highway.