one thing to keep in mind though, is race team swap out the darn internals as they please, this might be monthly, weekly or even after each race. i think he said he'd replaced the clutch, but was using the stock tranny. 3rd gear is the one that gives the most trouble, so maybe they beefed it up. if you look at the stuff Golden Eagle puts out their i'm sure they can build a couple pieces to make it a bit tougher. they are damn hard to get a hold of, phone is much easier than email for these guys, but they are very cool once you get a hold of them.
i know the Xtrac was modified to replace the stock piece in the mazda6's in the speedworld challenge. but i think that would be a bit out of most peoples budgets for daily drivers.