Two Convertibles with some similarities, but otherwise different in most aspects such as the modifications, horsepower, fuel economy, height, and maximum occupancy. First of all, the 2016 Porsche Boxster has bigger and thirstier engine; the 2015 BMW 2 Series Convertible M235i gets 3 more mpg. Also, the 2015 2 Series Convertible M235i is slightly taller than the 2016 Boxster. In addition, there is a difference in the number of passengers; the 2 Series Convertible M235i seats two more the Boxster. Among similarities are the body structure, market segment, starting price, and ground shadow size.