Two Sedans with some similarities, but otherwise different in most aspects such as the model year, horsepower, fuel economy, ground shadow size, and height. First of all, the 2013 MKS has bigger and thirstier engine; the 2016 A6 gets 5.1 more mpg. Also, the A6 is both slightly smaller and shorter than the MKS. Among similarities are the body structure, market segment, starting price, and maximum occupancy.