I'm using their 18 inch polished, 3in inlet and dual 2.5 outlets, factory muffler-back pipes, resonators, and tips. I have had it on for 1500 miles so far, no rattle, nice mellow tone at idle and cruising, sounds awesome when u stab some meat in the throttle. Factory resonators make all the difference in keeping the drone under control when the MDS kicks in and drops to 4cyl
I've been going back and forth on this issue for the last few days. Listening to all the Youtube exhaust clips, the 18" Magnaflow sounds the best to me. I'm really worried about the MDS sound though. Without the radio on, I can hear the MDS with the stock exhaust. I can't make myself pull the trigger.
I took some videos of my exhaust yesterday to do a comparison if I decide to put a different muffler on. I was shocked at how quiet the stock exhaust it. It's actually louder inside the truck then it is on the outside. I can't make up my mind.