Two Convertibles with some similarities, but otherwise different in most aspects such as the modifications, starting price, fuel economy, ground shadow size, height, horsepower, and maximum occupancy. First of all, the 2016 Mercedes-Benz SLK-Class AMG SLK 55 is priced $419,400 lower compared to the base MSRP of the 2016 Rolls-Royce Phantom Drophead Coupe. Also, the 2016 Phantom Drophead Coupe has bigger and thirstier engine; the 2016 SLK-Class AMG SLK 55 gets 8 more mpg. In addition, the SLK-Class AMG SLK 55 is both significantly smaller and shorter than the Phantom Drophead Coupe. And then, the Rolls-Royce Phantom Drophead Coupe seats two more passengers than the Mercedes-Benz SLK-Class AMG SLK 55. Among similarities are the body structure and market segment.