I “once”, bought a toy race car. That was nice because, I’d open a second car and stuff it into the box of another race car. I’d have 2 cars in one box. Then I’d buy that one box. These were like slot cars, but some components were upgradable. Engine, tires, bumper wheels, and batteries. The difference between these cars and slot cars were, contact to the track was made on the sides, of the track and car. The track has a wall along it.