LOL I just checked that scene again and as soon as the car spins around after getting hit I think I see what looks like casters just to the inside of the front driver side wheel. You can see it if you freeze it at just the right time. Though the car when stationary doesn’t particularly look like it’s raised. Still looks like it’s standing on its own wheels. So I don’t know how much those casters helped spin it around. But maybe they did.

As for the chain on the rear bumper I still can’t make sense what the other end could be attached to. The rear bumper is obscured by a small bush and I just can’t see what it could have been attached to. An anvil behind the bush? Lol. There just isn’t anything big enough there to attach that chain to from the bumper.