4] On Layer 1 copy 2 cut out the front wheel so you are left with this :- http://img96.echo.cx/img96/4519/frontwheel7fi.jpg
and then do the same to the back wheel but one the next layer down (Layer 1 copy). You should be left with the front wheel on one layer, the back wheel on the next layer and the whole picture on the last layer.
6] Now bring your fully sized wheel layers onto the squashed car and line them up so it looks like this :- http://img204.echo.cx/img204/7341/wheelson7yr.jpg
as you can see it looks very rough so all thats left to do is to use the eraser(& the clone tool if needed) and clean up the wheel arches so it blends into the car and you should be left with something like this.
