Got my +3s in this week. I can repeat what I said after installing them on my '12... best mod for these trucks, hands down. Bigger price tag for what they are, but worth it.
With my bedrack, and after out last trip, my stock leafs had sagged quite a bit. I'm now back up to stock height with all the gear in bed. May settle some still, and still don't have my rear winch mounted but hoped for a slight front high stance. Currently perfectly level with 3" collars @ a little over 42" fender to ground in all corners. I did get the rear shackles to drop the rear, but held off installing to see how much it settles and keep the cushier ride for the time being