You can check PFYC.com, clubgpstore.com, intense-racing.com, and various other sites to get the best price. As for brand, I really don't think tha brand will matter.
Gains will be at the lower end, it won't help you much at the top end, unless you get a PCM also. You get a PCM to go along with the pulley at it'll pull all the way through.
Don't forget to factor in a pulley puller aling with the pulley. You'll need to use the correct puller in order to remove the pulley.
**DO NOT USE A 3-FINGER STYLE PULLER!**
If you use the incorrect tool, you will end up damaging the pulley beyond repair.
You might be able to find someone to loan you the puller. That'll save you on the puller and help keep your cost down.
Good luck, and happy motoring!!!
_________________________
Bobby
Died 5/1/08, resurrected 5/15/08
ASCD SD hood, 17" Bullitts, Overkill PCM, 3.4" Pulley, NGK TR55IX, K&N 9" cone filter, JimmyC D/P, U-bend removed, Flowmaster 40 series, Hooker big bore tips with resonators, S/B brake lines, drilled/slot rotors, GMPP handling kit, KYB struts, F&R strut supports, HID's, LED's, 2.5" Air Dam, red GTP overlays on custom badges, white rear insert.