I'm a Cali driver but only in the high desert, i don't think the side exhaust is illegal because svo's have them. My buddy up here has side exhaust and never had any trouble. As for the turbo, don't drive crazy and I'm sure most of the cops won't even know or care. Down the hill honda's get reamed for everything not so much muscle cars unless you're very loud and being stupid. Our state law says we can't be lowered with in a certain amount of inches but I see stangs lowered all the time, even mine is dropped 1.5 all the way around. Once again honda's get the poop stick on the lowering part as I've yet to here I got pulled over because my mustang was too low. But yes you can get pulled over for the turbo with out carb numbers, yes lowering our cars too much is illegal, no body kits are not illegal and the side exhaust I'm sure is fine... At least where I live. I haven't had any problems in rancho, Colton, San Diego, and riverside when I go out driving the guys.