Jop, I'm glad you did that upgrade. I agree:
1. RV should "drive OK" as delivered
2. Components, like springs, can deteriorate
3. Aftermarket products will not correct underlying problems
4. Alignment, weight distribution and tire pressure are essential
Still, even one that drives OK will drive better with things like upgraded sway bars, better shocks, etc. As an example, ours drove poorly, all over the road, when we bought it. Prev owners full timed in it for 3-yrs, 30,000 miles. I don't know how they stood it. Steering linkage was worn out. With new linkage and an alignment it "drove OK." We could have stopped at "OK" but sway bars made it much better. Track bar made it better still.