dunno of this is out of your way, but there is one in el monte that is worth going to. i have stumbled upon a few exhaust shops. the first few, not so good. first one i went to was called tonys muffler, very unprofessional and even lets their children weld for you -____-. BUT i stumbled upon a place called mikes muffler, very nice guy, very honest and he knows exactly what he is doing. whatever questions you have hell be able to answer it . he is fair with price as well, sometimes even negotiable. on yelp.com hes 5/5 stars and he didnt even know about it until i told him. he said, " i feel the best way to do business is by being honest." even if its out of your way its worth going over there.
here check it out :
http://www.yelp.com/biz/mikes-muffler-shop-el-monte
manytimes youll go to an exhaust ship and thell wait for you to tell them what you wanna do, but sometimes your not too sure of what you want to do just ask mike and he can help you out with some options.
i paid 110 for new 2.25 inch pipes, a resonator, and to weld on my exhaust.
and another time i paid 50 bucks for him to put on my WSP.