Muffler or Cat

[riley501]

If you could only do one delete which would it be and why? I have heard from some the muffler is most restrictive get rid of it, other say cat is, does anyone here have the correct answer. Which one will sound better, which one will perform better.

[dusthol]

both are restrictive. i deleted my muffler, good sound no performance gains. if i had to do over i would delete all of it.

[07OUTLAW]

GET RID OF IT ALL!!!!

I also did the muffler first..... sounded better, no drop in EGT's

Then I did the cat, sounded even better, EGT's dropped.

Looking at both I'd say the cat is prob more resrictive, I'm not sure though. I'd say just straight pipe it, or do an aftermarket 4" with cat delete and "high flow" muffler.

[stk1130]

Definately delete both. I was concerned too before I straight piped my exhaust and didnt want to delete the cat. My friend convinced me to delete both and Im so glad I did. Not only does it sound really nice (not too loud but loud enough to turn heads) my egt's also dropped.

[Manatee]

Depends on your state and what they look for during inspections. It's legal to remove your muffler, but NOT your cat. Soem states care, others don't.

[03-blue-Powerstroke]

I would say the muffler. I had full straight pipe for 2 years but I got sick of putting the cat back on for inspection so I left it on.