Have a 2001 E450 with a 23 foot Coachhouse. Terrible ride originally. First - - replaced ENTIRE rear leaf spring suspension with a Reyco Granning air suspension (real thing - - not just little air bags like Firestone etc). Then bought Koni shocks - - before the FSD was available for this chassis. Still rough so sent shocks back to Koni for revalving. Still not happy but finally Koni made FSD for this chassis so ordered and installed them. Quite decent ride and handling now. Info in greater detail if you email me at rhaag11@charter.net