So where do they differ? The C63 AMG Black Series is based on a newer W204 chassis and the M156 motor is updated with newer/stronger internals from the SLS and a slightly more aggressive tune. Acceleration between the two is very close in stock form and the C63 Black Series is rated 10 horses higher at 510 versus the older CLK63 AMG BS. Car and Driver puts the acceleration of the C63 Black Series as slightly faster than the CLK63 Black Series with its 1/4 mile sprint of 12.2@118 versus 12.4@116 for the CLK. The CLK63 BS curb weight is 3918 pounds while the C63 BS is a little heavier at 4,044 pounds (Car and Driver does not provide the very important curb weight figures). This means for the C63 Black Series to trap slightly higher with more weight it has to be putting out a little more power which may explain the dyno numbers hit recently that CLK63 AMG Black Series owners seems to not be able to believe.
These cars are not about raw acceleration numbers though as much as performance on the track which is their design goal. So which is better at that task?
For a comparison about track performance Car and Driver sure spends a lot of time talking about the CLK63 AMG BS interior as being dated. They also complain about the seats. It's as if they are surprised the cabin is all business with track performance in mind. The CLK63 Black Series seats are fine as is the cabin speaking from experience. Sure it does not offer modern luxuries and comfort but it isn't supposed to. It's a Black Series Car and Driver not an S-Class, come on now.
Skidpad numbers put the C63 at .93g and the CLK63 at .96g surprisingly. The steering of the C63 is said to be lighter and not quite as tight although the chassis is more responsive offering more feedback. It is also said to be more comfortable. It also offers more stability control and shifting options as a newer car usually will. So which car set the faster laptime?
We don't know. Car and Driver actually took both these cars on the road course and gave us acceleration and skidpad numbers instead of the most vital piece of information which would be the laptime numbers making for a complete failure of a comparison. It should be criminal to not provide the most important part of this comparison and a publication like Car and Driver sure as hell should know better. So, that basically makes this comparison video a waste of time and worthless. We don't need a 7 minute and 47 second video about someone's subjective opinions but at the very least should have some cold hard facts/data out of it. The reviewer, Basem Wasef, states on his Twitter account that he is proud of 100,000 views for this video. This is a video that would never be put out by BenzBoost as it simply does not meet BenzBoost or enthusiast standards as a serious comparison piece.