Had my 2011 AF 811S (slide-out) on a 2004 GMC Sierra 2500HD 4X4 with rear hellwig swaybar, Rancho 9000 adjustable shocks, extra leaf spring, air bags, Vision 19.5 wheel/tires combo and a 2" levelling kit at the front. Not sure but the levelling kit may have impacted the typical GM front low "stance" & balance. The end results were that I was white knuckling it the whole time particularly on narrow bumpy roads, so much that it felt the front end was airborne at times. Thousands wasted. Less than a year later I bought a 2008 F-350 4X4 short box dually with camper package, 19.5 wheel/tires combo, air bags and I added Torqlift uppers. The difference is day and night!