not seen how CLK engines are laid out, but most supercharged engines with rootes style blowers cant have an intercooler as they bolted directly to the inlet (check out jackson racing supercharged civics and focus for example) so water injection is the first/only choice.

dont be suprised how high charge temps will be either, esp if not intercooled theyd be v.high. ive seen standard intercooled turbo cars still have have temps well over 60degC, so may well be bad on 230K's, dunno, but deffo dont discount it without checking it out.

many manufacturers delberatley make zorsts restrictive, charge temps high, boost too low, etc etc etc to keep the power down, as any higher and itd make buying the next model up totally pointless fo example...