hi there hamilton ont Canada here we also have an indoor off road carpet track . I have the losi 22 i just did the change also to a gear diff many ppls use them at our track here also. I did on the other hand use 18k in it only because this is all i had at hand ,but to tell you the truth the stock ball diff was ok for awile but i found myself always wanting to tighen it so id get less unloading and more push.i ended up changing it because i wore the ball's out(very crunchy) so bad by early last week i might as well had a locked diff i will rebuild it but for now its gear diff.i didnt need to shim or anything and right away(probably because the ball diff was shot) wow what a nice upgrade for sure very smooth id say it felt better then day one i race every friday and it last almost 30 race thus far so not to bad

Another great mod or upgrade was too dremel the rear were the camber links go Ball"s end up pulkling them selve"s out and ovaling the hole out,so what weve done is dremel under it and add a nut no more issues after that.