Two Convertibles with some similarities, but otherwise different in most aspects such as the starting price, height, horsepower, ground shadow size, and maximum occupancy. First of all, the 2018 BMW 2 Series Convertible is priced $25,150 lower compared to the base MSRP of the 2018 Alfa Romeo 4C Spider. Also, the 2018 4C Spider produces fewer horsepower than the 2018 2 Series Convertible. In addition, the 4C Spider is both slightly smaller and significantly shorter than the 2 Series Convertible. And finally, there is a difference in the number of passengers; the BMW 2 Series Convertible seats two more the Alfa Romeo 4C Spider. Among similarities are the body structure, market segment, and fuel economy.