That's the trouble with Mercedes engines, they are already very efficient from the factory, the easy stuff like the ECU and CAI and exhaust are the cheapest and easily modified parts. After that it will continue to cost us more and more money just to squeeze out another 10 hp.

This is why the Turbo, or s/c is the way to go for cheap power for most cars being sold. If an aftermarket company can put together a decent Turbo or supercharger kit under $6,500 they will have the market on the Crossfire, in fact I think a lot of crossfire owners sell the car because there isn't a reasonably priced boost kit out there.
If only we could get someone to build it and operate the software to run the damn thing.