Unfortunatley that's going to have to be a question posed to someone else who's running with them. I'm a firm believer in not buying anything new unless what's old is broken, or just plain crap to begin with.

To date - I have purchased:

1. New wing mount
2. Upgraded Aluminum rear chasis brace
3. RC Screwz kit for the RC8 (which I've gone to a few times)
4. Mugen Gaskets for Center Diff
5. New shock oils (27.5 / 32.5)

That's it! I've been running it hard and haven't had any major issues, but rest assured when something breaks, if it has an upgrade I'll be buying it . I can let you know at that time how it works out