The high flow cat will be quiet at a stop, I am not so sure you will get what you want with any exhaust and the high flow cat except maybe leave it stock and just change the cat. The Solo Mach is about the best of all possible worlds, with or without the high flow cat. The cat makes a lot of noise. I would try the Mach system and then add the cat later if you want more noise. It's harder to install the cat than it is the exhaust.
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Solo Mach and High Flow Cat
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