Towing my 3023 w/kia sedona

Well, we just came back from our first trip with our 3023. We had a weight dist. set-up for a 600lbs rating installed and we took out 3 of the seats in the van which weigh approx 50 lbs each. The van has a towing rating of 3500 lbs and i know that we were very close to that (if not a little over it). The equilizing hitch sure brought the back end higher but i noticed while we were driving, it felt a little shaky and bouncy at times. Is this anything to worry about? I felt no lack of power at any time. We even removed the 2 propane tanks and the battery from the front to lighten up the load. Thanks for any suggestions.