Well, if you go higher than 1.5-2", you're going to need new upper control arms to avoid clanging into your coil bucket. You can either buy the RC kit, or buy pieces and make your own. You will probably spend more on UCAs if you buy pieces, but you'll get better quality. You will definitely get better quality with the 5100s than just about any other standard shock out there. Coilovers are a different matter entirely, but they are also 3-5x the price.
What you will need, if you don't go pre-built kit, is UCAs, shocks, spacers, sway bar links, and extended front bump stops, for the front, and blocks and shocks for the rear unless you want that goofy nose-up look. How much rear block depends on how much rake you want to keep. You can consider that 2" in front will be roughly level with stock rear, so 3" front would need 1" rear to be level, 2" rear for 1" of forward rake, etc.
Not sure what any of this does to your air bags, but I think nothing. They work on top of the spring, if I'm remembering correctly how those kits work on Titans, so blocks in back won't change their geometry.
I'm about to lift my 2011 Pro4X, and here's what I'm doing: I'm using PRG UCAs, 5100s front, set at middle setting. That should give me 3" front lift. Rear will be 1" lift shackles and 1.5" blocks, giving me 2.5" rear, and maintaining 1" of forward rake. With 2.5" lift, I'll be using 5125 rears to get the length and travel right. I'm making my own sway bar links for about half the price of what you can buy aftermarket, and I'll use Energy Suspension extended bump stops up front. Eventually I'd like to get a u-bolt flip kit for the rear and some extended bump stops, but that's another project for another day.
I've been advised to change out the lower front ball joints while I have it apart, but may take the easy route and just install new lower control arms. We'll see. I already have cam bolts so if you don't, count those in as something you'll need to get your alignment right.
