I installed a 2" lift autospring a couple of weeks ago on my 2006 KR 4X4 (it is very easy if you have a 24" breaker bar) and got the alignment done. I have few words of advice for people considering this (or for that matter any mod on any F150 front suspension):

1. It will be done better if you do it yourself than if you pay someone to do it. (I called one front end shop and told them I wanted to price having them install the lift and the guy said "Man let me check, that's a lot of work doing one of those" I hung up on him and did it myself, he was obviously salivating at the opportunity to rip me off.
2. Ford doesn't screw around with bolt torque, if it's a large bolt it needs to be TIGHT.
3. When you go to get the alignment done they will do more than just adjust the toe and if your not going to the dealership you should tell them that the lower control arm bolts need to be very, very tight or your alignment will not hold for long. Using an impact wrench is not enough, they need put a breaker bar and a cheater pipe on it (Ford dealer told me this after one of my control arms slipped in it's slotted bolt holes on my way home from my front end alignment).
4. Measure first, on my truck there was barely 2.5" of difference from front to rear in the stock ride height. A 2.5" front lift would have been too much.

There was no difference in ride quality except for a barely noticable condition called bump steer which is going to happen any time you rasie or lower a vehicle with rack and pinion steering and do not move the rack up or down as well.

Hope this helps anyone considering this mod.