I think that's a good idea, Adam. In my opinion, the nitto trail grapplers will make a bigger difference than new wheels. If you can swing the tune AND the tires I would do that. You can always get wheels later. Something to think about, too.... if you do the tune after you get the new tires, you can have the new tire size accounted for.
Hey, Adamn! To answer your question, I'm really not sure how that guys truck was set up. Based on what I've seen in the past and what I can see in the picture, I would be willing to bet that he's running a 2.5" leveling kit in the front with 18" wheels and roughly 33" tires.