The front stabilizer bar uses the same bolts and nuts that are already holding the stock v6 bar on. The bar should come with the bushings already on it, you just slip the bracket over the bushing and replace the v6 bar with the GT bar.
The rear bar will need some bolts and nuts since the v6 (except pony packages) does not come with a rear anti-sway bar. I went to the Ford dealership and they told me it would cost $45+ for 6 nuts and bolts so I got the sizes from the Ford parts dept. and bought them at a local Auto-Hardware store for around $10.
You'll need 6 bolts & locking nuts to match them;
4 - 10mmx30mm bolts, 4 - 10mm locking nuts
2 - 12mmx65mm bolts, 2 - 12mm locking nuts
When I bought mine they didn't have 12x65, they had 12x60 or 12x70 so I went with the 70 and they worked just fine. I also had to put a washer to keep the links from shimmying around inside the brackets on the car, again; no big deal.
Make sure you get locking nuts so ensure that they dont come off and if you need some pics of how its supposed to look when its done let me know, i'll be happy to snap some and post them for you.
Oh and - have fun!
Black 2005 Mustang v6, 5 speed, IUP, EUP and Leather.
Razzi 1/4 window scoops, Mustang GT Sway Bars, Flowmaster American Thunder Single Exhaust, Clear Front Turn Signal Lenses, Demolet CAI, X-cal2 91 tune, Hurst Comp/Plus Shifter, FRPP T-Lock, Ford 3.73 gears