I'm curious. How do you position the chisel. Is is supposed to act like an impact driver?

 

Stamford,

How many miles on yours?

 

82,000 miles and change. Runs like a top but I imagine the trans fluid is reaching the end of its useful life. And since I have the bark, I assume it's the original "good for life" fluid in there. Do wish I had a lift, though.

 

I should post a picture but it's getting late.
These Torx screws have a big flat head so put the chisel on one side of the head, angled at 45° and (obviously) pointing in the 'unscrew' direction, then give it a smart tap with a medium weight hammer.
It is indeed similar in effect to an impact driver but, with these screws, the force is applied on a much larger diameter than with a Torx bit so is more effective.

 

Shot a vid on the way home from Mollis, yep mine has the bark as well....

 

Are you placing the chisel on the outer edge or inside the torx pattern? Having seen the hassles Sam had with the screws, I am hoping my car has the bigger screws but even those could be good and stuck.

 

On the 'flange' of the screw right outside the tiny Torx pattern. That way you get enormous purchase.