Kyosho has addressed the bladder issue by releasing foams to place under the bladder, I haven't tried this yet but I do know that type of volume compensator works in other shocks I've built. So far I have very few problems with bladders ripping because I don't over tighten the shock caps, they work, don't tear and don't leak.
OK, I understand what you meant about cheaper Mugen parts on fleabay. K parts can cost more than retail there (for the good stuff like clutches, unis and diffs).
All in all, I beat many other brands on the track and many other brands beat me. At the end of the day I'm still having fun and haven't spent a small fortune on which buggy d'jour is popular at the moment. Heck, if you're good you can still compete with a MP7.5 on the local level.