bay area?? CA??? well i can tell you where not to go, Andy's Autosport. They will rip you off. There is a shop called Kustom Workshop up in Concord that I heard does a pretty decent job at stuff. If all else fails i'm sure a dealer will put it on for you.
Razo(Milpitas)-decent store, pay in cash they might not charge you sales tax. They have a lot of kits laying around and exhaust systems.
Autoware One(san jose)-only go there if you REALLY REALLY have to.
Modacar(Pleasanton)-decent store, you can check out their webpage www.modacar.com
Carboy(oakland)-I haven't been there before
Autofreak(SF)-too many accesories and not enough performance
Bill's Auto(san jose)-ok place to go, kinda overpriced though
Auto Innovation(milpitas)-more of an installation shop
J Motorsports(milpitas)-alright shop to go to, but not my first choice
I know there is a place in Hayward but I forgot the name of it but it was a pretty good store. If your going for installations I wouldn't trust any of these guys to work on my car unless i really had to. Most of the stuff i buy i install it myself, the people who will install the parts on your car are usually boy racers who do a piss poor job on it, about the only good job they do is clean out your wallet.
Well thats all i can think of off the top of my head. Hope that helps, if you need the addresses or directions let me know, i know where most of these shops are.