Your Palazzo tow weight maximum is 4K#'s. Your Arcadia empty weight is listed at 3950#'s. if you have a full tank of fuel in the Arcadia, you are OVER the tow weight maximum for your Palazzo. If you have supplies, food, BBQ, bicycles, etc. in the Arcadia, then you could be WAY over the safe tow rating for you motor home. That might be why you say it's giving you a hard time.
DEFINATELY get a 4 wheel alignment ASAP. THOR may pay for this.
I have a Safe T Plus steering stabilizer in my motor home, and it improved steering feel substantially. As a safety precaution it is supposed to help keep the RV under control in the event of a front tire blowout.
However, NOTHING will take the place of keeping your tow vehicle, and your motor home within weight specifications while towing. You may have a 8K# trailer hitch on that Palazzo, but what you need to look at is tow vehicle weight, and combined weight rating. You may want to consider a smaller tow vehicle, something like a compact car.
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