Two Convertibles with some similarities, but otherwise different in most aspects such as the height, starting price, horsepower, fuel economy, ground shadow size, and maximum occupancy. First of all, there is a notable difference in the starting price of the 2018 Mercedes-Benz C-Class Convertible, which is $14,700 less than the base MSRP of the 2018 Alfa Romeo 4C Spider. Also, the 2018 C-Class Convertible has bigger and thirstier engine; the 2018 4C Spider gets 3 more mpg. In addition, the 4C Spider body is slightly smaller than the C-Class Convertible, and in addition to that, it's also significantly shorter. And finally, the Mercedes-Benz C-Class Convertible seats two more passengers than the Alfa Romeo 4C Spider. Among similarities are the body structure and market segment.