The 6.7 isn't going to as loud as a 5.9 because of the filters. A few people have tried removing the DPF and cat, butit's probably not the best idea.

 

so will the filter back exhaust on the 6.7 be louder than stock or not if someone has it on theres can u get me a sound clip please

 

I have the mbrp muffler delete single outlet on my 08 6.7 and can hardly tell the muffler is gone. the filter and cat remove most of the noise.
other than all the pipe matching in size all the way out now and the stainless looking cool. it is only makes a tade more noise.

 

Check out these photos. Click here

 

There is almost no sound gain at all. I have a 08 6.7 and I have the MBRP cool dual 4 inch and it was basically 500 bucks for looks. I dont know i there was any performance gain or not.

 

Is sound a gain that you are looking for? Sound does not make you go faster. Try pulling and grossing 26k up some of the hills on the BlueRidge. You will feel and see performance gains. Lower EGTs and a better breathing powerhouse.