guys that straight piped their rigs did you have to buy adapters from 3 1/2 to 4 inch for the peice of pipe. because i think on my 03 the pipe where the mufller is, is 3 1/2. Or are you able to put the 4 inch peice on and sqeeze it down and make it hold. Thanks for any input.

 

You're going to need an adapter or it's going to leak. Check your yellow pages for a truck parts store near you, or get one from Airflow Systems online.