We have an E450 and replaced both OEM sway bars with Hellwig bars. Same size and steel as Roadmaster but far less expensive. The new bars helped immensely, both on the road and on the campsite.
I visited with John at Hendersons Line Up in Grants Pass Oregon. One of the top shops in RV ride and handling. He agreed with the same 5-degrees of caster like Harvard mentioned above. Also said that adding a Safe-T-Plus steering stabilizer worked like setting caster to 5-degrees. It'd be the silver 31-140 model. The OEM damper brackets won't fit, you need a S-T-P bracket kit as well.
A Damper, like OEM and replacements from Monroe and Bilstein, absorb jolts. They don't help keep the steering centered. There's a kit called Steer Safe that centers the steering. Safe-T-Plus has hydraulic shock absorbing AND coil springs to center the steering. So does Roadmaster's "Reflex" unit but it uses one exposed spring instead of S-T-P's two enclosed springs. Henderson sells a lot of Roadmaster products, so if they select S-T-P instead, that's what I'd do.
