Deleted my muffler today. Left stock pipe and cat in place. It is quieter than I thought it would be, but don't think I want to take the cat out yet. It has a nice, deep, mellow tone it. Just enough to notice it. Crushing down the highway sounds damn near stock. Stomp on it it wakes up to a very deep v8 growl.

If this way my daily driver, I would probably get a 4" straight pipe kit...

 

I bet it spools up a lil' faster now????

 

The 6.0 has the most brutal roar when you stomp on it!

 

Agree with Dave06. Straight piped 6.0s are the best sounding when piped. My buddy has a 5" straight pipe on his 05 6.0 and it gives me a stinger each time he opens it up.

 

Mine is straight piped and it's brutal at WOT or towing at certain RPM's if you do go straight piped I would put a resonator on it to take a little bit of the bark and drone out of it. I went with the aluminized 4" Off Road kit from MBRP and I'm going to yank it off to replace it with the Stainless Steel version with a resonator.

 

^ that's exactly what I was afraid of too.