I know the 3 has one of its cats built into the exhaust manifold, which pretty much guarantees that if I install new headers, I will fail emission testing. (I live in Seattle.) My friend suggested to me that I might be able to take my car to a custom exhaust shop and have them cut out the section that contains the cat and somehow splice it into the line with custom made headers. Is this possible? Will it change the way the cats work, causing me to fail emmission testing anyway? Has anyone here ever tried this before? Your thoughts, please.

 

I have this same issue with my Corvette. Long tube headers would eliminate the "pup" cats and a visual inspection would result in failing the smog test. As far as I know, there's not much you can do; I wouldn't want to go through a header install and then have to remove everything after failing smog. Now a CAI intake system is a different matter......

 

all i can say is find a shop that is a certified emission inspection place and have them just pass you of course youll have to pay them and most likely you would have to get something installed by them first. I say this because thats whats happening for me