rezenclowd3 - There was a problem with the first 5R front arms breaking at the pillowball. They fixed that in June and the newer arms are a lot stronger. In fact I have yet to break the set I have been running since June. I was breaking the older ones every couple of weeks before that change.
If you are as much of a maintenance freak as you say, you will not have leaky diffs. The outdrive orings can wear eventually but keeping them greased up will help a lot. Even if you replace the orings once a month (overkill) you will still not be doing as much as you apparently have to do to your Losi.
You would seriously not consider a car because the only stock part that is only okay is the brakes? Avid brakes cost like $12 for the car. That is pretty much the only non stock part some of the pros use.
I do not understand why you are on the Mugen thread. You seemed to have your mind made up to keep your 8 before you even asked a question.