ps2cho, I never heard that before! I have a 91 300E and i've jumped it many times with no problem, still has the original OVP. I'm not really understanding how it could damage a part designed to protect against voltage surges, and with a fuse (or two) no less. I'm not saying you're info isn't right, but I've never heard of anyone having a problem like that after a jump and never seen any threads relating to it (unless some of the many "bad" OVP threads are the unwitting result of jump starts!).
Maybe just MB covering their asses with that TSB?

edited to add: I've also charged the battery in the car (with pos+ cable removed).