Well, I finally installed the lift. I installed new Bilstein 5100s and FJ 2010 springs in the four corners. The fronts were placed at 1.75" lift. Measurements are after alignment and 50 miles. The rear settled about 1/8" in that time, the front did not budge.
I have to say that this setup is living to its expectations. The ride is improved, a tiny stiffer, but not as much as the OMEs I had in my 3rd gen. The ride is just perfect. This week I am going for a 600 mile drive towing the boat so let's see how that goes.
Measurements before:
FL: 32 15/16" ; FR: 33 1/4"
RL: 35 1/2" ; RR: 35 3/8"
After:
FL: 35 5/16" ; FR: 35 1/2"
RL: 35 7/8" ; RR: 35 7/8"
So about 2 1/4" lift in front and 1/2" in rear. I still want a little bit more in the rear so I may install Cornfed's 1" spacers.
My ride is a 2008 4Runner 4wd V8 with 50k miles and stock 265/65R17 tires.
Bottom line: just do it! I did it alone and it took me the whole day, but was well worth it; including the front spring compression/installation. I will post some details and tips in another post.
EDIT: ok, so here is a report after 1,000 miles. 750 of those were towing a 4,500 lbs boat:
FL: 35 1/16" ; FR: 35 5/16"
RL: 35 5/8" ; RR: 35 1/2"
So a drop of about 1/4" all around..... I hope it stops sagging. I also measure at the running boards and I have about 1/8" rake front-to-rear, so rear spacers are coming on top of Firestone air springs for towing.