I read this whole post and no one asked if you had checked your lube level in the trans - it will run noisy if your low on lube. Check it if you haven't. Stock T5s have held up to some pretty high power levels and track duty, a LOT of it has to do with how good you are at shifting.
Thanks for the tip on the synchros Bob, is that a track only car - in other words would you recommend that synchro mod for the street?