I have the tungsten diff balls on order.
And a TA-05 36 tooth pulley because the 501x WE pulley my local hobby shop cannot
get in for some odd reason. I just hope the 3mm diff balls will fit a TA-05 pulley :/
I have also got the big tube of tamiya diff grease as well as an extra belt

.
People have been conplaining about the nitride coating comming off after a few shock rebuilds.
Mine is still coated after 3 re-builds. Suppose you have to just be careful...:/