TC, he spent about $2500. That does not include installation, because I helped him do it. Eclipse and Diamond Audio are high-end car audio equipment companies (Eclipse has been around for a while), and non of the big stores, like Circuit City sells them. You will have to go to a small store that specializes in car audio (Not Car Toys) to see and listen to that equipment.
I don't even think Circuit City could do the custom sub enclosure (but who knows). I am a big fan of the small "mom and pop" audio stores. They know a lot more about audio and installation. And they don't have some punk kid installing the stuff and then telling his friends where you live so they can go steal it.
I have done quite a few complete custom car audio installs. I get better with each one. I know a lot, but still have a lot to learn. Hi-Fi is a hobby of mine, and I listen to hi-end equipment in my home, so it just makes sense to have the same quality or close to the same quality in my car. Especially if you have a commute everyday. I have passed this love for good sounding music onto some of my friends.
Anyway, one speaker can sound different to a lot of people, and it just doesn't make sense to some people to spend $600 on a pair of speakers for your car. A friend of mine has installed tons of mods onto her Passat, and I tease her about, "when are we going to put in a "real" sound system?" She is happy with the stock system. Some people just want to listen to music, they miss a lot of the subtleties that the artist include, and they are fine with it.
Stopping the rambling, the best place to start is your budget, then we can go from there. I would be happy to recommend some stuff if you would like. Diamond has a product locator on their site if you put in your zip code. I don't really know any shops in Cali. I will post those pictures or have my friend do it.
Eclipse -
http://www.eclipse-web.com
Diamond Audio -
http://www.diamondaudio.com