I purchased their springs because I had Heavy Duty OME coils that rode really stiff. I don't have much armor, nor bumpers, or very much extra weight. But I can tell you, before when I had OME Coils they never sagged and they were meant for load carrying a all time. I never had to use a spacer.
With my new coils, poly 4.5" coils, they haven't sagged (been on 4 months) but I did have to put in a 1" spacer in the front just to level the rig out because it came pre raked...
The ride difference for me is night and day. Love the Poly coils better because I don't have any weight. But if I had to choose a company that had heavy duty ass coils made for running heavy loads all the time, I would take OME over Poly, Teraflex, and Pro Comp. I've had experience with those 3 companies.
Poly 4.5" Coil with some 40's will do the job.
Sorry to awaken an old thread but this thread is getting right to the issue that I'm currently facing. After 4 years and 32000 miles on my Full Traction 3" coils, they are sagging bad. I also recently added a rear bumper/tire carrier and front bumper with winch and with those additions, I dropped about 1.5". Additionally, when I load it up with camping gear, the rear sags horridly - to the point where it bottoms on small potholes (on dirt fire roads)..
So, I was planning on upgrading my coils to the PP/Synergy 4" coils but it was brought to my attention that those may provide "too much" lift. "Too much" in the sense of having a steep pinion, being top heavy, etc..
What that leaves me is with a decision to make between either MetalCloak 3.5" coils or PP/Synergy coils. I notice you have the 4.5" coils and I'm wondering how different they are from the 4" coils.. I have a "full" lift kit (all arms and trackbars are adjustable, etc.).
I'm currently running BFG KM2 35x12.5x15's, 3.75" BS. There is a good chance that my next tires will be 37's.