I wanted to purchase a mbrp 5 inch cat back system for my 2006 LLy. I was wondering if that is to much for a truck that just has a cold air intake kit. I read alot about you need to have 4 inch for stock and 5 inch for chipped trucks. As of know i had the muffler removed and had a peace welded in, the problem is the peace that is welded in has big bends and is a little smaller then the stock pipe, overall it made a big different doing just that . Do you guys feel i should go with the 5 inch cat back or leave it the way it is.