I recently had to replace a valve stem on a alloy wheel on a '81 240D. The tire shop put in a rubber one that slowly leaks. I've looked on line and found original benz ones for $40 or $50 each which seems a mite high. What after market stems will fit this wheel? Also, just as a matter of curiosity, how do the internal threads that hold the valve core get stripped? Also, I have a wheel from a '84 300sd which I think is slightly wider. If I put the tire on that rim how would it affect handling, steering etc.? It's a front wheel which I obviously could put on the back...so anyway...