[Overdriven]

The chassis braces I'm referring to are on the underside of the chassis, the transmission bolts go through them, and is where you'd attach a center skidplate. With alum bulks, skids, and chassis braces the structure will be hard to bend without a chassis even attached, lessening the chance of breaking a plastic chassis. Should be a bunch cheaper than the alum chassis options out there too.

Shimming diffs. I always shim the spider gears inside the cup as well as the ring and pinion. There's a sticky around here somewhere about how to do it, but tip for traxxas diffs. After you add a shim and are checking the mesh out, reattach the driveshafts. Because the shafts use pins, you need to make sure they will still go in, and also because putting the pin in can change the mesh of the gears.

Alum cases for the diffs may not be necessary either, the newer 4 bolt 3905 diff cases hold up pretty well too, alot better than the older models, but traxxas' shim job is nonexistant. As items wear they get sloppy real quick. That slop translates into shock loads on the drivetrain when accelerating or braking, and eventually broken parts.