So for the M05 diff set up
Bushing diff is better than stock Gear diff with extra washers for indoor carpet race? The ball diff any good?
I don't know for your application since I don't know your traction level, but if it wasn't for the new TA03 diff sets I already had in my parts bin, I would have just done the monkeyracing diff or the 3Racing oil diff.
Each time I have to crack open these Tamiya m-chassis halves just to get to the diff I think it's a joke. I also had to laugh when I tried sliding one of my full sized 5200mAh lipo's into my V2. It's bad enough I had to bend my motor's solder terminals just to get it to fit the V2. The Lipo did not fit through the rectangular hole either.
So I've been using the round housing Peak Lipo's..
If I ever do get ball diffs again for my m-chassis, I would go back to the M05 ball diffs as I do not need it super stiff, and it is adjustable from the outside.
Give the monkeyracing diff a try. It's working great on my near stock M05. Plus, he recommended drilling access holes for the little diff screws allowing adjustability from the outside.
EDIT: I'm going to do the monkeyracing diff in my GF01's and WildWilly2 this winter. Might do it on my kid's WildDagger too from yesteryear since he gets stuck from time to time on terrain. I will be making the shims out of transparency film and sandwiching them between the diff housing and the factory shim. Should cost me like.. nothing.