Just took the RV for a 400+ mile trip with the Helwig sway bar. Like many previous posters, it does make a very positive difference. Happy to say, not a snap, crackle, pop even a clunk.
Much improvement in overall handling even though I thought the original handling was fine.
1. Reduces substantially buffet from large trucks when traveling behind.
2. Reduces substantially big truck push when they are passing.
3. Better crosswind stability.
4. Better cornering
5. Better recovery when crossing rough thresholds.
Well worth the minimal investment.