I usually carry a spare kit but here's a starter list:
- F/R arm
- Ball link ends
- Shock ends
- Shock shaft F/R
- Hinge pins inner and outter rear
- Ring/ pinion (just 1 of each)
- A bearing kit for your car
- Misc screws
That's a start and there may be other parts that your specific car breaks frequently that you may want to cary 2 of. I haven't driven a rc8 so I'm unaware if it's list. Also invest in some tuning parts: F/R swaybars and springs. Hit the RC8 thread and find out wants working on that car, then I would go a couple steps up and down from there on these tuning parts.