Dan:
According to Kleemanns Technical Manager Cory Umemoto, the supercharger goes on the "stock" 3.2 block with zero internal mods. He said that they have done a number of superchargers on the motors in the SLK with "NO" power train issues. As we know it is the same engine and train as ours. The power is 330 hp plus a ECU chip which costs $1,000 and adds 20 hp and 300 rpm. If you send me a personal e-mail; I will forward the correspondence that I had with him.
With just the supercharger, 330hp plus the chip 350hp, so if you do any work on the short block, or heads who knows? He did say that our power train can handle 400 ft-lbs continuous torque without modifications and the Super Charger and chip is around 345 ft-lbs torque ><.