I have a buddy with a 6.0 that had muffler delete. It sounds great. Can you do that to a 6.4 without needing a tune? I know the 6.4 has dpf but I'm not sure if thats located in the down pipe, the muffler, or what.

 

you can do a dpf back exhaust without tuning.. its not really going to do anything performance wise.. if you wanted to do a full exhaust on your 6.4.. you would need either the delete pipes for the DPF and Cat.. or a full 4" or 5" Turbo back exhaust, both of those would require a tuner.. but just a dpf back exhaust wont require any tuning

 

And it doesn't do anything sound wise either. The piece on the stock exhaust after the DPF is actually a resonator to give it more sound. These things are so quiet they had to add a resonator to give it some kind of sound.

 

Even with a full delete, mine just sounds like rushing air all the time, not really grunty or engine sound, more like a jet airplane lol..

No engine sound, no turbo sound, just rushing air.