There is a 100 of them you can talk to. RET in downey, CA more known as one of the best 4v tuners in So Cal if not the country. But I'm sure they can help.
GTR is in Rancho Cucamonga, CA You see them alot in magazines they do good work.
MMR is in Oxanard, CA they have some very fast race cars, some people don't like them much.
coast high performance is in torrance, ca
Chicane motorsports is also in torrance, CA I have seen some of there cars and they are very nice.
That should be enough to get you started. There is plenty more if you don't like those.