On topic:
I'm not sure many drivers would prefer the CLK430 on the track vs the C43 due to the performance (drivetrain and suspension) differences.

Also, forced induction eliminates most of the difference between the AMG 4.3 and the standard 4.3 - a supercharger negates intake and cam differences (so says Kleeman, Renntech, others). However, the AMG setup should be more durable for a supercharger setup due to the internals having been strengthened already...

By the way, the C43 does feel very comparable to a mid-90s or 80s 911 IMO (having driven 911s). The straight-line acceleration numbers even bear this out if you check...