Two Convertibles with more similarities, such as the body structure, market segment, starting price, ground shadow size, height, and maximum occupancy, than differences, like the horsepower and fuel economy. And finally, the 2015 Audi RS 5 Convertible has a more powerful engine and gets 2 mpg less than the 2016 BMW M4 Convertible. Among similarities are the body structure, market segment, starting price, ground shadow size, height, and maximum occupancy.