I love the hiss and your absolutely right in regards to the sound with climbing rpms. And Since I have a stillen exhaust it's naturally pretty quite and has a low tone so with test pipes it doesn't sound like a pack of mosquitos flying towards me. I love the smell as well but I'd like to try and stay "under the radar" and the smell seems to be a lot stronger now and that's why I'm thinking that there is a leak right underneath me which is why the smell is getting into my window soo easily. I love the test pipes but I don't like the "Service Engine Soon" light so the only reason that I would go back to stock cats is because I don't like having dash lights in my face.
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Z 
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