I thought my response was kind of funny. Be that as it may, if you're going to keep the car forever, and are just looking for a more "fun" ride out of it, do it. If you are ever going to want/need to resell it, don't. People who buy used MBZ's want stock (you'll note that people on this thread even keep their old stock radios, wheels, sway bars, etc., after they upgrade). If you DO want to mate a 5-speed, why not try to get a MBZ 5-speed (1986-88 300E's, early 300SL's, etc.) In ANY case, if you do not have your own machine shop (as I believe somebody suggested), it is going to be expensive. Good luck.