We had a Tiger Trak bar from Ultra RV installed and I don't have the tail wag now - that was huge. (We also have the Safe-T Plus steering stabilizer, but that improvement was less noticeable.) Not sure what your specific handling issue is, but I didn't upgrade the sway bar and don't plan to - my symptom was wagging after passing or being passed or in side wind. Our unit was 10 years old and 62,000 miles so I went ahead and replaced the shocks with Koni shocks as well. The unit handles very well now, but I'm thinking the trac bar was the biggest bang for the buck.
2010 Georgetown 350TS
2012 Ford Fiesta tagalong