Snowie, I'd be cautious of relocating the wing without understanding the flow characteristics over the cabin area. It isn't as simple as just lifting it, the angle has to be adjusted as well as the semi-attached flow over the the car comes down onto the wing at a pretty extreme angle. Just lookihg at the standard one shows that the leading section would cause almost zero downforce in an undisturbed airflow. This would leave most of the work to the upper adjustable winglet. I'd suspect that most of the aftermarket mounts would change the angle of attack to compensate. While I know a lot about aerodynamics, I have a friend who is Fords top aerodynamicist so if you get me a lot of good pics I can ask her to take a look and help me with an adjustment angle. Getting the mounts machined then won't cost too much and I can suggest some stiffening solutions so the bootlid doesn't crumple.
I'd also recommend getting those undetrays, maybe in fiberglass.