Rear Springs
Ended up going with 2" Icon dual rate springs with the Air Lifts. Couldn't be happier with the results!
Really feels like the rear soaks up everything now. Didn't really have any complaints about the spacer's ride quality, but was also not expecting this much of a difference from going to a spring lift. They are a bit softer than I was expecting over little stuff, but in a welcome way.
Install was pretty straight forward and not too intimidating, but definitely was helped by all the threads on here. It's definitely worth disconnecting shocks, brake line / ABS brackets and sway bar as described by everyone instead of trying to be a cool guy and pry springs in there. I think it would be much less time consuming and easier to use two jacks to jack the axle up and down on opposite side more than you think you need, instead of doing a bit at a time and checking for fit. If I had to do it again, I would just make as much space as possible for the new spring by jacking the axle up and down heavy duty the first time around.
No wheel re-inventing here, but here was my process for rear springs in case this comes up in a search:
Drop Spare tire.
Disconnect rear sway bar links from axle (4 bolts) and swing / secure out of the way. (easier to do with truck on the ground)
Loosen Wheel Nuts.
Jack up rear (my 19" floor jack didn't even come close to lifting high enough with 33"s without adding wood).
Place Jack stands.
Remove wheels and place under frame for added security.
Disconnect wire bracket on axle.
Disconnect brake line bracket on lower control arm.
Remove lower shock bolts and pry shocks off shock mounts.
Jack up one side of the axle near lower shock mount.
Use 4Runner bottle jack + wood spacer on opposite side to push down the axle. (not necessary to remove the old spring, but was required for me to put in the longer coils without lifting the axle too much to the point where it was lifting the truck off the jack stands.)
Pull out old spring / Bump stop spring cone
Put bump stop cone on new spring and re-insert (making sure the spring is sitting correctly in the obvious notch on the axle)
Slowly lower bottle jack
Slowly lower axle on opposing side.
Repeat for 2nd side.
When you are done and lowering the axle on the side opposite of where you inserted the last spring, you have an opportunity to reconnect the shock without having to jack it up again later. (Tap in with rubber mallet)
Jack up side with the shock that still needs to be connected to align shock mount with shock. Reconnect shock. (Tap in with rubber mallet and tighten shock bolt)
Reattach wire bracket on axle.
Reattach brake line brackets on lower control arms.
Re-mount tires.
Remove axle stands.
Drop truck.
Reconnect sway bar.
I did after 3 years of di(#$ng around. Bilstein's 5100 all around and OME coils all around. With the air lifts 
