What were your pressures before the work was done?
Michelin's Chart suggests about 5 PSI less for both Front and Rear, using the Chart the way they want you to. Specifically, the "RV" chart I linked here wants CORNER Weights. The "Truck" version is Axle Weights. That's because Michelin believes RV's are more likely to be unevenly loaded side-to-side than cargo trucks are. Michelin wants Corner Weights to make sure an axle that falls within its total rating isn't overloaded on one corner. They recommend inflating both front/all four rear tires according to the heavier corner. You clearly are not overloaded in any Corner, Axle, Side, or Total. Interestingly, if I had weighed YOUR coach the way I weighed ours, on a CAT Scale at a Truck Stop, I probably would have set pressures still lower, about 10 PSI less than Henderson's recommended.
Theorists, thinking of very light, all-out performance track cars, will say that too stiff a sway bar can cause "Under/Oversteer" depending on where the imbalance occurs. Their technical concepts aren't wrong, but a Class C RV operates in an entirely different envelope than a race car. Like an airliner vs. a fighter. Class C's can use all the "roll stiffness" (from Sway Bars) that you can find. I can agree that a stiff Sway Bar will transmit a part of pothole shock to the opposite corner. And I can agree that the Track Bar is an Axle-to-Frame connection that Ford didn't put there. Both add a little "unsprung weight" which those theorists'll say is bad. And is part of the justification for alloy wheels vs. steel. Still, the Track Bar is nearly horizontal. It just isn't going to have much leverage to transmit impact shock from Axle vertically to Frame.
Here's about all I can offer:
1. The FSD's may very well "break in." A country boy friend had a shop and we installed new front struts in a Toyota I had and I said "Wow, they're Stiff!" to which he replied "They'll limber up." and they did.
2. It's possible that the very hard poly bushings in the Sway and Track Bars and possibly the FSD's are sending a little more jolt to the coach in the cause of tighter handling control.
3. Call Henderson's if you haven't. See what they say. They won't tell you anything they don't believe to be true.
4. When I talked with John about Class C tracking, he said a Safe-T-Plus and rear Track Bar usually solve the problem. When I re-read the list of new parts you added, I started to think you might have gone there. I remain convinced you could not have done any better.
If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB
