[AaronR]

The word need, NEED, NEED!!11! keeps coming up but I think you should to replace "need" with "drastically improves".

No doubt, I agree, high quality diff balls, the 18T center pulleys, better ball cups and studs, etc., etc., are drastic improvements but not NEEDED to win races. Give a box stock 501X to any pro/experienced driver and they will wheel it around a track well.

P.S. There is one NEEDED item for the 501X that I almost forgot about... Tamiya or JAAD diff covers. I race indoor, low dust off-road and the diffs without covers still accumulate dirt and grime.

Lastly, best of luck with your B44! Without question that is a great car, but no car is perfect.