Two Sedans with some similarities, but otherwise different in most aspects such as the model year, modifications, market segment, starting price, horsepower, and fuel economy. First of all, there is a notable difference in the starting price of the 2016 Acura TLX, which is $3,285 less than the base MSRP of the 2013 Buick Regal GS, which is three model years older. Also, the 2013 Regal GS has bigger and thirstier engine; the 2016 TLX gets 4.5 more mpg. Among similarities are the body structure, ground shadow size, height, and maximum occupancy.