Anything is possible, as long as local laws permit it.
in souther california, you will have a hard time with local smog laws by putting different engines in different cars.
I think the law here states that if you put another engine in an older car it has to be an engine that came with another year of the car, but cannot be older than your year.
I am not sure on this though.
I do know someone has put a 560 engine ina 190E. It might be possible to get a C36 Engine with a Manual Tranny from a European version if they made them like that. That would make the car a real screamer if you ask me.
The SLK Engine might work. If I was going to do an SLK Engine, I'd use a kompressor of course.
I'm not a tech, but I dream of dropping a C36 engine into my 300CE. For my car the C36 engine should fit without a problem (same basic block I believe, but then wiring, tranny, diff, etc might all have to be worked on to make it all work right.
either that or I'd have the thing complete rebuilt and bored and tuned by a tuner.
Alon