I haven't damaged the diff gears at least on the gear faces. The gears being nylon is the issue however. I was just curious if it'd be worth it to piece together.

The diff I got is the case, spur and pinion; However I run a modified metal WR02 driveshaft pinion on both ends of the driveshaft.
They appear to be the same screws as the WR02 standard diff? I have leftovers of those.
I feel the metal gears with the pin drive cups would be more robust here. I've got the metal lock block in the front diff so it's not an issue up front.
I'll see if it's worth it to build or buy complete. Either way would work.