What we have here are two Sedans from Cadillac with some differences, such as the model year, starting price, horsepower, fuel economy, and ground shadow size. First of all, there is a notable difference in the starting price of the 2016 Cadillac ATS, which is $5,880 less than the base MSRP of the 2013 Cadillac CTS, which is three model years older. Also, the 2013 CTS has bigger and thirstier engine; the 2016 ATS gets 2.7 more mpg. And finally, the ATS is slightly smaller than the CTS. Among similarities are the body structure, market segment, height, and maximum occupancy.