So I searched around but I couldnt find any info on going 4” exhaust or 5” for the 6.7. I know the DEF back doesn’t do anything, this will be more for cosmetics. MBRP as a 4“ black exhaust that I want but Banks has the 5“ monster. So if I decide to get an exhaust, would it be better or worse going 4” or 5”? I don’t think the 5” will do anything for me with the DEF system and never getting a bigger turbo.... Just curious.... Thanks all