I have never used those, but I had dealer install Rancho 9000's, an extra rear leaf, then crank up my front torsion bars when I bought my 05. Almost 200,000 miles later, they are as stiff as new. I leave em cranked to max.
Inertia Spartan + cam, Circle D 3,000 stall ,Sonnax line pressure booster, MagHytec 68RE pan,and differential cover, Vararam, JBA's with cut outs, Rancho 9000's, Helwig rear sway bar,3:92's, extra rear leaf,Line-X Bedliner,GY Armortracs, 245,000 miles To Hell and back. 14.2/96 mph NEDW