Two Convertibles with some similarities, but otherwise different in most aspects such as the modifications, starting price, horsepower, height, fuel economy, ground shadow size, and maximum occupancy. First of all, there is a notable difference in the starting price of the 2019 BMW 2 Series M240i Convertible, which is $15,500 less than the base MSRP of the 2018 Alfa Romeo 4C Spider. Also, the 2019 2 Series M240i Convertible has a more powerful engine than the 2018 4C Spider, and it gets 4 fewer miles on a gallon of fuel. In addition, not only 4C Spider is slightly smaller, but it's also significantly shorter than the 2 Series M240i Convertible. And then, there is a difference in the number of passengers; the BMW 2 Series M240i Convertible seats two more the Alfa Romeo 4C Spider. Among similarities are the body structure and market segment.