At school we bought a Titan Lifts 4500. It has 6 casters (4 on the ends and 2 in the center) and large wheels for any surface. Very sturdy and stable. Comes with a lot of adapters to mount the car. I drilled the all tubing so that the set screws go through to lock the tubes in place. Just makes it safer for the kids. We're building a Mustang on it right now.
