The shock problem is easily fixable. I just put 4 mm of fuel tubing on the outside of the shaft. The problem is that the Mugen shockshafts are too long. On a hard landing, the shaft is actually slamming into the top of the shock. The fuel tubing prevents this. The diff problems can be fixed by replacing the internal gears with EB-4 gears(steel instead of the Mugen Aluminum), or you can shim the regular diffs so that you get rid of some of the play. You just have to recheck them often, because as they wear, they will develop more play.