On my 426 stroker I have long tube headers, 3 inch pipes all the way, with two resonators before the mufflers, 2 borla x mufflers and 2 resonators after the mufflers. It is still a little a bit loud with the stock insulation. On the outside it sounds awesome but inside I would like it a little bit quieter. If I was to do it again I would go with the dynomax turbo but the opposite side in/out so its the real design and not the split chamber one.
