You did also flip the track bar on the front. I would go with the air bags. I hate stiff springs. Also look into upgrading the brakes . Put brakes on the trailer if possible. With a 1800 pound trailer you want 10-15% of that in tongue weight for stability. When towing keep the tire PSI up. Good luck. The high CG and short WB is not your friend in towing. Go slow and look ahead.