I can't help on the spring change, because My Rubi springs are more than enough with the RC 2.5" spacers, but--
I can reccommend the RS9000XL (adj) springs, they are reallly a boon to comfy/controllable riding-
You can set them for hiwy with/without load or very tight control for rocks/ruts/gravel off-road and towing !!
There are 9 seperate "points" on the adjustments, but you can't feel the diff. between EACH setting, so you'll develop probably FOUR set points (I do)-
Coilover shocks are very expensive and you have to modify your shock mounting points-more for competition and racing !!