be real glad you did not buy Rustys, springs are rated same as stock and will sag quick, rear shocks are best thrown over the hill and never installed
Spacer lifts are junk pretty much
Now with that said, Daystar is OK but only for newer vehicles. After 30-40,000 miles not worth it since your springs are already sagging.
Now for a DD, and can you lift safely. I know a lot of people who have a ton of miles on with no problems. My first full OME spring lift I took off after it had 100,000 miles on it. Many others have the same. I'm on my second lift, KJs has over 153,000 miles over 130,000 miles lifted
If you go with new springs go OME
Now would I install the Monroe preloads, No for several reasons, I like a better ride, I like a better handling vehicle than stock and I want some thing that will last for a while.
Lifts for a KJ are not expensive when compared to other makes, for 700-800 in parts you'll have a great lift with all of the benefits. Doesn't have to be a rock crawler, you want a better ride don't you?