Running a thrust bearing instead of a normal washer setup and silicon nitride diff balls makes a diff pretty much bomb-proof. Sanding rings is old-school, it's easier to get prepped rings from someone like Tuning Haus. With this combo I glue the ring to the axle so it won't move and just drive. The only downside to the silicon nitride diff ball that I can find is that when you re-assemble the diff with these non-metal balls you can have problems getting the ball to bite the surface of the ring if you use too much grease, but sometimes the diff seems to be almost completely dry and runs just fine.