Torx Screws

I was looking over my engine last night, and noticed that GM put 2 different kinds of torx screws on the car.
Some are the standard type torx screw, and some have a center stud in them.
Why 2 different types?? Where can 1 find a driver that has a hole for the center stud?

Just curious.

Where'd you find the studded screws? Usually thats a form of security so the standard homebrew DIYer can't unscrew the fastener and then end up blaming GM if something goes horribly wrong (ie things exploding for no reason). As far as I know, Sears still has some of those security-type torx bits, and of course the Big Boys like Snap-On and Matco stock them.

Still, I'm interested to know where you found them at. Unless its something critical to the operation or safety of the vehicle, it should just be a regular torx...

I found them(center stud) on the MAF sensor and the TPS.
But on the the IAC it was the standard torx screw.

I bought a couple sets over at NAPA.

I have three sets of those torx set.I have a Female torx socket set,a theftproof set and a torxbit set.They do come in handy,My neighbor and my father borrow them sometimes.Two sets that I have are made by Sk tools and one I have is made by Stanley.

My TPS was screwed with regular screws without studs. But usually I break those studs using flat screwdriver, so I can use standard torx screwdriver.
P.S. I didn't suggest you to break them :)