Okay I emailed the guys at the Kansas City Spring place to get the low down on the keys, here is his reply

"The basics of it are they set the preload level at an earlier point. The front end will reach the factory load sooner which is how the height is achieved. They are all well within factory specs. Yes, they will put a little extra wear on the front end parts such as cv, but it is minimal and you'd be changing them maybe a year sooner than you would be without having the keys in. Once these are installed and give you 2" then you still have the option of turning the bolt up for more height, but this will stiffen the ride because of the key angle being / instead of --....hope this helps"

So I am still on the fence. I will have to check to see what I am exactly off as far as level. Then a 3" body lift once we sell the travel trailer and get a motor home. Weeeeeeeeee.

 

I got the 2 inches of lift out of mine after installing them but need just over a 1/2 an inch more to level it. That minor of an adjustment shouldn't adversely effect the ride quality. I couldn't see spending all that extra money on a lift kit and installation when I can already fit 35's under it if I wanted to.