[simplechamp]

For internals, probably Hot Bodies hardened steel gears. Then maybe an alloy case, and most hardened steel spurs should work fine. Just stay away from the cheaper alloy or pot metal gears used in some diffs. Using thicker fluids will help to ensure the diffs don't unload too much in the front or side to side, causing extra wear on the gears.

Really though, Slipperential is a great option, you get the alloy case and hardened steel spur, but also the slipper protects the gears and will make them last longer.