SO, what about swapping out the stock downpipe? My thoughts are now 3" MBRP downpipe, 5" straight pipe with muffler. The question then is what happens to the connectors that are currently located on or by the cat etc. Also, can I do that prior to updating my efi Live or do I need to get returned prior to doing that? Also, would just doing the downpipe do anything for me? The problem I am having is finding a good diesel performance place here in Cincinnati to just do all of that or to just CALL ME BACK. Frustrating as I'm willing to pay to get it done, just having trouble finding some place to do the down pipe, exhaust and retune the EFI live.