Built mine a while back.
Started off a a stock XB, then fitted a 25amp Toro Micro brushless setup with a 1500 mah lipo. I had to replace the body with an SC one to fit the ESC in.
Then fitted new Animus diffs..... followed by aluminium dogbones, aluminium wheels, aluminium centre driveshaft, and today a rear diff pinion.
I may be making too much power.
Even with the punch control on max its a bit wild.