1. Choose a side angle shot.
2. Select out the wheels individually, make sure to leave a bit of the floor and the arches, and past them into a new layer.
3. Hide the two wheel layers.
4. Use the free transform tool to squash your car to a reasonable level.
5. Un-hide the wheel layers and then move them to the required position.
6. Use the erase and smudge tool (or whatever that suits you) to merge the wheels into the background image to look reasonably realistic, and you are done.