I have an 08 Ford Mustang GT. I bought a nav unit off of ebay that was in an 06 F250. I'm not sure if this was the original vehicle, but everything seems to work so far when it comes to the radio. My problem is the 7p nav disc I just purchased is reading as an invalid disc. I thought that it should work being that it is a later version. Is there something wrong w/ the disc or unit, or is there a specific version of the map disc need?