Two Coupes with some similarities, but otherwise different in most aspects such as the modifications, starting price, horsepower, fuel economy, height, and maximum occupancy. First of all, there is a $122,235 difference in the base MSRP. The 2016 Porsche 911 Coupe R has a higher starting price than the 2016 Cadillac ATS-V Coupe. Also, the 2016 911 Coupe R has bigger and thirstier engine; the 2016 ATS-V Coupe gets 3 more mpg. In addition, the roofline of the ATS-V Coupe is slightly higher than the 911 Coupe R's. And then, the Cadillac ATS-V Coupe seats two more passengers than the Porsche 911 Coupe R. Among similarities are the body structure, market segment, and ground shadow size.