I am not sure about the resonator on your 6.7L truck, mine in California has catalyst, DPF, and muffler. I thought all 6.7L where setup the same .... I removed the muffler and installing a 5" DPF back exhaust had no change in sound. The catalyst and DPF is muffling everything. If you do a complete smog delete, you will need a resonator and muffler to quiet it back down to normal. If sounds too much, they will get you. I know a person at work with 5.9 and open pipes, wow, loud, still can figure out why he has not be ticketed yet.

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