Here's my two cents on 6.7 air intakes:
If you want something that's going to fit like a factory part, go with the S&B. If you want the most performance potential, go with the NL Stage 2. I've run both on the same truck with the same mods, and if I could do it all over again, I would have gone with the No Limit in the first place.
The S&B worked fine... It did its job, the installation was simple/clean, and I ran it for about 80K on my truck. Even with the Street-Max turbo, the truck ran well. What I mean by that is the filter minder never got sucked in, so the S&B wasn't starving the turbo for air. That being said, I always thought that the truck would run better with a NL intake, but it was never a priority.
Then, I thought I'd give the No Limit Stage 2 a try to see if it lived up to all the hype. The installation pissed me off... No matter which way I oriented the intake, it would find a way to rub on something. I finally got it setup "good enough" and decided to go for a drive.
My initial impression was that the off-the-line performance suffered in comparison to how the truck drove with the S&B. A quick email to Morgan for some revised tunes took care of that though. Between the intake itself and tunes designed to work with it, my truck REALLY woke up. The truck just drives better now. Period.
I guess the moral of the story is that as long as you're open minded about fitment and get the right tunes, the intake is a worthwhile upgrade. Don't get me wrong, it still bugs me how crammed in there that thing is, but the end result was worth the grief.