It's pretty easy, I installed them on 2 of my old trucks. A stock 3/4 ton, CTD, and a 1500, that already had a 6" lift, I just stacked the spacer on top of the 6" spring. You don't need a spring compresser. Just a jack and a couple jack stands.
I just did my shocks and the springs almost "fell" out. I didn't loosen anything other than the lower shock bolt/nut and the shock tower. (I had the truck on stands, under the frame, and then lowered the jack from under the spring/shock assembly.) I should have done my springs at the same time.
I hear that the 3/4 ton springs will give the same effect as the spacer. You might want to look into different pricing options.
I am installing a Skyjacker 2" lift coil springs on my 1500 this weekend (and AAL in the rear). I'll post some pics. The rep at Skyjacker said they give as much lift as using a 2500 spring, but they are designed to have a spring rate/feel within 10% of the stock 1500 spring that it is replacing. So, it should still ride about the same. I'll let you all know if this is true once I get it done.