Well as I always say, "no kill like overkill". I always look at this stuff from a risk standpoint. If you are qualified to setup a new LSD and ring and pinion then there is minimal risk. If you have to send it out well then there's one level of risk. That was part of my decision to go with a newer used Subaru R180. It also comes down to driving style. beat the crap out of it on every shift (I approve) then you would want to overbuild.