There's some really good advice on this thread. Good idea.
I have a couple...
- If you find yourself tearing your diff case apart at a track, spray your car down with a light mist of WD40 to keep the dust in it's place and not falling into where it's not supposed to be.
- Don't listen to the guy always giving you advice, listen to the guy that keeps beating you. There's always someone at the track that THINKS they know everything but can very well be completely wrong.