That sway happens when there isnt enuff weight on the ball. WHen you load the car backwards with the motor hangind past the rear wheels of the trailer it gives you a light tongue weight on the trailer. This will cause the sway. the setup mechanic is talking about is more then just sway control. It also is load leveling system that transfers some of the weight up and threw the chasis of the tow vehicle. Almost everyone I know who tail drags a camper uses this system and you would be amazed the direfernce it makes on the level of the tow vehicle with and without it on.