ok...basically this is how it goes...as someone already said the law is basically written in a way that says anything that is not stock is illegal...now here's the facts...as a domestic owner and someone that has worked on hundreds of performance domestics...and someone that has several officers as friends(state and city cops)...imports will get fucked with before the domestic will...even if the domestic is 2 times as loud.it sucks,and it's not right...but that's the way it happens right now...too many fucking young ass dumb kids driving stuidly all the time have ruined the import image as far as the law is concerned.you can prolly get away with it(putting the exhaust on)...but if you get a ticket...your best bet is to just pay it and let it go.