Two Sedans with more similarities, such as the body structure, market segment, starting price, height, and maximum occupancy, than differences, like the horsepower, fuel economy, and ground shadow size. First of all, the 2016 Cadillac ATS has bigger and thirstier engine; the 2015 Acura TLX gets 2.3 more mpg. And finally, the body structure of 2015 TLX is slightly larger than that of the 2016 ATS. Among similarities are the body structure, market segment, starting price, height, and maximum occupancy.