Automatic or manual leveling kits

Our 31-ft Class C/E-450 became more stable with front and rear Hellwig Sway Bars, than it was on the HWH Kick Down Jacks and OEM front and rear sway bars that are standard on E-450.

I don't see how that could possibly be true. Sitting on a suspension, the frame is going to float on the suspension. No matter how rigid your suspension is, as long as it has shocks and springs it's going to give - that is what suspension does.

Sitting on jacks, the frame isn't going anywhere.