The engine used in the CSL had increased output over the regular S54 by and over the European M3. This is due to the use of sharper profile camshafts, a bigger air intake a with carbon fibre manifold, a refinement of the exhaust manifold, and slightly different exhaust valves. The top speed was electronically limited as standard, but buyers with a current motorsport licence could order the CSL with the speed limiter removed. The sole transmission available was the 6-speed SMG II automated transmission, with revised software resulting in shift times of 80 milliseconds.