Yes and yes... although not dramatic by any means. Maybe 10-15hp, maybe.
I started with an aFe Rebel side exit exhaust, it was loud and aggressive. Then after DPs it became ridiculous, it was soo loud that the interior door panels were rattling! You literally couldn't hold a conversation inside the truck while cruising. So I went back to factory exhaust for now and it actually is pretty nice.
Unfortunately without cats it's ricer/raspy inside the cab, but by the time it makes it through the (factory) exhaust it becomes more throaty so outside it's a nice step up in both volume and aggressiveness. Cruising is quiet, no drone, but anything over 1/3 throttle and 3k+ rpm and it opens up pretty good.
My suggestion to anyone is start with DPs before you even think about exhaust, catless if you don't mind rasp and want more volume, hi-flow catted if you want a lower rumble and quieter. (given the opportunity, I would go catted next time)
I do however have a little beef with Stainless Works at this point... I like the idea of going to a flat mating surface over the factory "adapter flange" for increased flow, however the exhaust if very rigid and I doubt it flexes nearly as much as the engine mounts. Also, more importantly the DPs are now the lowest part of the truck! It sits about 3/4"-1" lower than the factory skid plates. Imagine hitting a rock when off roading, not only will it tear up the exhaust but it most likely will damage the turbos/headers.
I brought this to the attention of Stainless Works, they seemed to be genuinely concerned and since only one of them really "off roads" he was the one who really understood the issue. He asked for me to send him pictures, which I did however I have yet to hear a response.
Between 5 Star taking 2+ weeks for the tune and Stainless Works 2+ weeks no response, I feel like a whiney a-b when even talking about it...