Given that the legs move a little bit, I would suggest adding at least a small amount of bracing in addition to whatever you choose to do to fix the center of gravity problem.
Also, bracing helps to stiffen the structure by resisting forces that would make the wooden rectangle into a parallelogram. Here is an illustration:


Even with a car payment being $750/month, that's a pretty fancy car from my perspective - and represents the average car payment for a new car.
I think that these folks could keep up with expenses much more easily if a few minor compromises were made (namely, a cheaper car).