Oceannanna,
I had a full size Dodge 250 van conversion, and I did not have to have a sway bar attached to the weight distribution hitch. After buying the new Durango, I experienced sway when pulling the 3326 King. The Durango has a shorter wheel base and can cause the problem. The same will be true with your Explorer. Spend the $125.00 for the sway bar, and you will have pece of mind when motoring down the highway.
Buy the Trailmanor and the required towing accesories, and you will be happy!!
Bob Strong