bay car stereo on Geary is pretty cheap. had my jeep done there. also in marin there is a place off of francisco blvd i forgot the name but its like famous. WAAY too expensive but its like the place 4tyson used so if ur into to that U SHOUDL DEF check it out. sorry i cant remember the name right now.
i guess its kinda shady but i had a friend who worked there so he hooked me up with a good deal. JL audio 12 JL audio amp. altec lansing amp back speakers, clarion front speakers and a alpine head unit about 1500 with install. i wouldnt trust em for custom stuff but for regular installs they are pretty good.