Do double stacks, they look so weird with single stack on them. All the points made about the stacks in the bed are true except for the droning and discomfort from the passengers. The cabs on our superduties are well made and are still pretty quiet. Yea there is a diff between the stock exhaust and if you put the full 4" turbo back with stacks on yer truck but its not that bad. I can really hear it with my window down and my extended cab window vented open. I just hear the whistling more. Def make sure you keep yer cargo tied down. Sucks when a trash bag gets away from me and hits the hot pipe. My truck is a shortbed and since its already short, I wasnt losin much bed space anyways. Thats what trailers are for. I get alot of compliments on my stacks, and the sound is so sweet. Wouldnt change it at all.
MBRP has their smokers kit which what I have. I was gonna get a 5" stack kit but MBRP doesnt make it. They only go 6" or bigger. They had a few other stack choices you could choose from. Grandrock makes a kit too. Def do it right and get Stainless. Yer already spendin alot on the exhaust, might as well pay more and get the good stuff so you dont have to do this again. Hardest part on installing my kit was havin to cut the old down pipe out. Other than that not bad. One thing to note on MBRP's kit, their stack clamps suck! They would bottom out pretty much before they were tight. You can upgrade clamps but more money.