I can talk you through some of the stuff, it can be done but it is not going to be cheap, but definatley buy OEM parts to update the exterior as most aftermarket stuff (grilles, lights, tails) looks cheap and will eventually fall apart. As for the interior, anything is possible, check out MBenzNL, you will be paying big money for the amps, antennas, programming, removal of D2b system, MOST wiring, etc and will likely have to do alot of research youreslf, learn some german, or pay an expert who has done it before (not many have).