i bought mine from ford, although i cant remember the exact cost (i *think* it was around $50). took me 10 minutes to replace. there is no need to remove the tire (although you may find it easier). i did not have to remove the fender liner, there is a hole in the liner to allow the connector to pass through. the connectors in the engine bay were right by the cruise control module IIRC.
as said before they are easily damaged when removing them. your best bet is to get a new one since it will also go in easier. good luck!