what willineed to do to install a car stock on my preban ar? special tools?

you will only need a telestock wrench. Bushmaster has them. Just use the same springs and pins from the back of the receiver. Be careful not to lose these during disassembly. It is really quick to do.
One more thing. I'd rec some locktite on the telestock locking ring.

if you plan to leave the CAR stock on, you can also stake the ring in place.  Lotboy's came loose when we were shooting so i staked it for him.

I just wrapped a rag around the tube, then used some vice grips(not too tight) to tighten it. I didn't use locktite, but it might not be a bad idea, just watch out for that little spring that's gonna pop out if you have a stock installed already.

markm, excuse the dumb ?, but how do you stake the ring?

Quoted: markm, excuse the dumb ?, but how do you stake the ring?

It's not a dumb question.

there are three notches on the stock ring. depending on where the ring ends up when you thread it on, you should be able to stake the plate (or spacer) on two of the notches.

all you do is get a hammer and chisel like tool(something narrower than the notch) and stamp the spacer so that some of the material bends (if you will) into the notch on the ring.  just a little bit will do. it will ensure that your ring doesn't come loose when shooting.

Thank you, sir!