who's running stacks on there cummins also any sound clips. my MBRP 5" turbo back is a little quite and iam thinking with the new wheels and tires it will look better with the stacks

 

Stacks are for looks. 4" straight pipe will make as much if not more power.

 

I have stacks on my 99.. Also have done several installs on CR Cummins, as well as Fords and Chebbys..
Heres an 04

Here is mine:

They basically sound just like a straight piped 4" system, it just sounds louder since the exhaust exits right behind the cab..