When messing with one of them bolts I always take a small pointed object and completely CLEAN out the torx holes...COMPLETELY.. Then I use the hammer driver on them.
If the wrench is not bottomed out and seated completely... problems arise.
You may be able to WHACK em to get them broke loose and do a bit of grinding on an oversize tool to meke it a bit smaller and then get it to fight tightly enough to get the bolt out. If not then here comes the "easyout".
If the bolts are on the rollcage or the frame one might be able to grind two parrell sides on the bolt head and get a wrench to fit and unscrew them. Never forget to WHACK em a good whack will break loose the rust and helps most frozen bolts.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />