I need a little help on this one…

I was considering buying a hi-flow cat for my FD and I was just wondering if I would still be emissions legal (in Colorado) with dp, hi-flow cat, and cat-back?

 

assuming that your emissions is like CANADIAN standards I would say there should not be a problem(legal)..it is afterall ..a catalytic converter that is functional..keep the spec sheet ..

 

if you mean like a visual or something that should pass. as for the test, i would also guess it would. my fc did for both the above with an aftermarket cat and header, so i dont see why not. all i can suggest is make sure the airpump is goin strong and hooked up, and change your plugs right before! no matter how new they are!