The shifter is direct bolt in. No chopping or hacking, but you will have the newer style shifter gate, you will have to buy a new shift knob because I don't think they swap over.
I just purchased a W203 3.67 diff today, $130 w/tax locally. I also have a R129 large pumpkin w/3.69 still in the blue C36 my friend totaled, it may just be good for r/p swap like you are interested in, since the entire rear subframe is taco'd beyond belief.