If they have magnetic train why not use it for cars suspension. It would cause a nice float but instantly stiffen. Some what like gm uses for their shocks with metallic flux which causes it to thicken by adjusting voltage to them for instant response.
My car is no lower , and i get my air from costco still. They never hassle me but i usually bring the wheels off the car by themselves. Their is a place on lakeshore that will fill for $20 but the guy was a real prick the last time i went so i no longer recommend then.