Sport Auto magazine, the Auto-motor und-sport group sport magazine, made a comparison test between the BMW M6 Cabrio with Competition Package (575 HP) against the Mercedes SL 63 AMG (585 HP).
At first glance, these cars are not really from the same segment. The SL 63 AMG is a classical roadster with two seats, while the BMW M6 cabrio is a full four seats cabrio. Belonging to different worlds, the Mercedes SL 63 AMG has a weight advantage with a kerbweight of 1,819 kg, while the BMW M6 Cabrio weights 2,007 kg.
The BMW M6 Cabrio features the Competition Package (8,500 euro extra) which includes, above 15 HP increase, sport suspension and a modified M differential.
Since June 2017, Mercedes gave up the base version with 537 HP and the Performance Package version with 565 HP and all the SL 63 AMG models are powered by the M 157 5.5 liter V8 bi-turbo with 585 HP.
Although the Competition Package is primarly intended to improve the driving dynamics, the sprinter qualities had also been improved. The M6 Cabrio sprints in 4.3, respectively 13.3 seconds to 100 km/h, respectively 200 km/h, which means an improvement of 0.1/0.2 seconds.
With 21 HP more power, the Mercedes SL 63 AMG is also quicker in the sprint from 0 to 100 and 200 km/h with 0.1, respectively 0.3 seconds.
The braking performances are also impressive, especially because both cars were equipped with ceramic brake discs, which cost the additional 8,270 euro for the Mercedes and 8,800 euro for the BMW.
The Mercedes stopped from 100 km/h to standstill in 36.7 meters, followed by the BMW with 36.9 meters.
Both cars are also at the same level when we speak about the transformation operation from coupe to cabrio and vice-versa. The electrical textile roof of BMW M6 Cabrio went down in 19 seconds, while the Mercedes needs exactly the same time to retract the rigid electro-hydraulic roof with panoramic glass (2,500 euro optional).
But when it came to artistic impressions, we found huge differences. The BMW V8 bi-turbo engine has an artifficial bass in its sound, while the Mercedes V8 AMG sounds throaty. But in both cases, we missed the emotional naturally carnival sounds of the previous M6 and SL 63 AMG V8 high-rev aspirated engines.
The German tester notes that the BMW 7-speed DKG gearbox reacts more spontaneous than the AMG Speedshift MCT in the Mercedes. You do not know either how often the electronics of the SL really releases the full power, but the ESP lamp flashes very rarely. But in the BMW, we have a totally opposite situation. In quick curves or when you pass short bumps, the ESP lamp flashes like a billboard in New York Times Square.
On Hockenheim short course, Mercedes had demonstrated the superiority of its huge torque of 900 Nm compared with 680 Nm for BMW: 1:13.1 minutes for Mercedes, compared with the 1:14.7 minutes for the BMW.
If you understand German, you can read the full article