If a new rig does not ride and drive well from the factory you are probably looking at the wrong motorhome
From what I've determined, then I'd rule out anything bigger than a small class B on the E series following your direction-due to handling. But thing is, I wanted an E series-due to the engine, transmission, availability of service, and general durability.
The E450 sway bars, shocks and possibly more are designed for a load that has lower center of gravity and is more forward than nearly any motorhome in my opinion.
What it boils down to is a value judgement on your part that the unit is fine out of the box. I feel it isn't. But I wouldn't give advice that those who want to change a few handling parts in their motorhome are looking at/bought the wrong one. It aint that simple. :S