If you use the Ford HID's they will cost you about $700.00 per side, thats $1400.00 to upgrade the headlights. I would like to have them for my car, and if I was going to do it I would want the factory lights, but I just can't justify the money for the upgrade. Too much money for too little.
One of the aftermarket light housing manufacturers needs to make a replacement housing that LOOKS like the factory HID housing but accepts a standard 9007 capsule. Installing an aftermarket HID kit in those housings would yield a system much like factory from the outside at a much reduced cost.