[zx10guy]

I've got a couple of ideas. First, you might want to try a T55 bit. Not sure how much bigger it will be over the T50. Use a hammer to drive the T55 into the damaged teeth of the bolt. And then try backing it out. If you have access to an impact gun, that would be the preferable tool to use. This may end up damaging the T55 bit.

Second idea is if there is enough surface space on the head of the Torx bolt and clearance around it, you might try using a set of vice grips.

 

[zx10guy]

If those torx bolts are tightened down with any decent amount of torque, forget about using that screwdriver trick. I'd try using a bigger torx bit first as I think you'll have better luck that way. If that doesn't work, then you can still attempt this screwdriver trick. Cutting a slot in the bolt to do the screwdriver trick will pretty much eliminate the option to try using the oversized torx bit.