Two Convertibles with more similarities, such as the body structure, market segment, ground shadow size, height, and maximum occupancy, than differences, like the modifications, starting price, horsepower, and fuel economy. First of all, there is a $130,400 difference in the base MSRP. The 2015 Bentley Continental GT Convertible Speed has a higher starting price than the 2016 BMW M6 Convertible. Also, the 2015 Continental GT Convertible Speed has bigger and thirstier engine; the 2016 M6 Convertible gets 1 more mpg. Among similarities are the body structure, market segment, ground shadow size, height, and maximum occupancy.