For some reason, TOB noise is pretty common. Mine started about 20K. The clutch holds fine, its just a pain. To be sure its a TOB, see if it stops squeaking when you push in the clutch. If it does, its probably a TOB.
I hooked my prochamber up with the stock bolts. I was able to get it tight with no leaks, but be sure to periodically check to make sure the nuts haven't come loose. Mine did after about 6 months. The best way to check for a leak-in my opinion- is to put the car up (while cold), turn it on, and feel around the conections for air leaking out. You have to move quick though.