I haven't been active on SF for a number of years for that very reason. A lot of ignorant people spewing a bunch of crap and those who are knowledgeable spend more time chest thumping and demanding milk money from the newbies.
Contact the folks at MarlinCrawler directly or post on their forum
http://board.marlincrawler.com/ . It's not entirely their thing but they and their customer base have a real knack for finding weaknesses in drive trains and the R150 is a direct relative to the R154 and they have a lot in common. You could also check in with Aaron's crew at DriftMotion and see if anyone's posted anything over at SupraMania.
I think I once saw someone selling a 'race' rebuild kit but I can't for the life of me remember who. I do not know of anyone who has done anything more than a regular rebuild even for medium/high power applications. The R154 is a beast but once you get beyond its abilities then you probably need to look into swapping in something with a greater aftermarket parts availability.