Sorry, I'm not as familiar with XTerra's, so I'll have some questions.
1. Do the PRG kits not typically come with the coilovers?
2. I've read that the Titan Swap will net you 2" of extra axle width on each side. Any thoughts to what you'll do to match up the rear? Instead of wheel spacers, does a Titan rear axle plug and play? (I'm not a fan of wheel spacers - personal experience, lol)
3. The Titan swap is good for, what 3-4" of lift in the front? Are you planning on for the rear, or perhaps lift springs, such as Alcans/Old Man Emu's (which I would recommend against Add-A-Leaf's)?
4. Also - is there a reason why you prefer the Rad-Flo's over the Sway-Aways?
5. What gear ratio do you currently have in the rear? It looks like the M205 front axle (the most likely swap candidate for a 4x4 conversion, from a Nissan Titan) comes stock with a 3.36 ratio. You'll want front and rear to match, of course.
6. What size tire are you planning to run after the 3" body lift + 3-4" Titan Swap? You may want to consider reagearing for your final tire size at the same time that you put the lockers in, to save on labor costs. Have the 4.10's come out yet for the Nissan axles?
7. Any thoughts to swapping in Titan outers as well (knuckles, spindles, brakes, etc) for 1/2 ton braking? Bolt pattern would change from 6 lun on 4.5 to 6 lug on 5.5, but with bigger tires comes wider wheels in many cases. Plus, if you did the Titan rear axle at the same time, then the bolt pattern would match.
This looks like a good thread: