Ron Carter 5-Star Promise: We Deliver Cadillac Test Drives to Your Door, We Will Beat Any other New Cadillac Dealer offer by $1,000, We Will Buy Your Car for $500 More Than Anyone, Loaners for Owners Delivered to Your Door. See Ron Carter for details. The CT6 competes with full size luxury cars such as the BMW 7-series, the Audi A8 and the Mercedes-Benz S-Class.. You better not buy until you see this car. This vehicle's sunroof is the perfect way to accent a road trip. Great fuel economy (EPA estimated 21 MPG combined) to fit perfectly into your budget. This CT6 includes: rear view camera, anti-theft system, a cabin air filtration system, cruise control and airbags. Offers to purchase may only be made following purchaser test drive. No dealers.