I don't mind in cab resonation. I used to have a HOT small block 350 with 3" straight duals. My thoughts were if it's too loud, you too old!

 

i went to a local muffler shop put on a 4'' glass pack had them install it backwards so it doesnt inpair the flow at all and a 5'' tip sounds great outside and not loud in the cab at all cost 120 for everything

 

Just put a straight pipe on the ol' 5.9, i love it. I dont know if its because I have a Mega Cab, but i dont notice any in-cab resonation on the highway until I hit 75 MPH.

 

Maybe just replace your stock muffler with a Aeroturbine 4040XL.

 

I love the sound of my 07, and it came with a straight pipe, only reason im goin to a 4" Stainless MBRP exhaust is because i want the power and MPG back and the pipe on it now isn't stainless.

 

you could prob go to a local shop that does 4" and have them make the pipes with flared ends so you would just have to cut um out and put the new pieces in place. just IMO nothing aginst it but flex pipe is kind of half way doing it, it is cheep and easy but not necessarily the best IMO

 

ya, an the flex pipe will rust out eventualy and break from the flex from the engine

 

Does removing the muffler and putting a straight pipe in its place increase mileage?