I guess I'm not understanding why you don't have confidence in the parts on the older bike. You've endo-ed on it, why? Are the parts somehow to blame? If they survived the crash and still work, then they sound awesome to me. Why the lack of confidence on technical trails? Skill and technique are much more important in those circumstances.
It's hard to make suggestions about future parts and bikes when you don't know what's wrong with the old. Upgrade your skills first. It's far cheaper than bike parts.