Just as an FYI there are two designs of the MFT/SYNC2 screen. Your brackets will only work with one of them. That would be the one that has a completely flat side.
A normal GPS antenna with a blue fakra connector is what you are looking for. The GPSM is mounted under the center dash speaker bezel. I would remove it and mount the GPS antenna there.
I have a non nav and nav sync3 setup available. Both are fully functional.
Non-Nav w/gps antenna - $950 shipped.
Nav w/gps antenna - $1350 shipped.
These will be programmed for use. I do have one set of mustang screen brackets for those going from a 4.2" screen otherwise you can use...
SYNC3 uses a different display than SYNC2. So you will need both screen and display. The brackets will transfer from your SYNC2 display if you have Mustang brackets. I also have access to a select few screen/apim setups.
Ford put out a notice that they are investigating this. The solution is simple...implementing it will cost them which is why they are trying to find a cheap way to do it rather than just fix it now.
Adding HD radio requires the ACM be replaced with one that has HD and then programmed to your vehicle. The APIM should also be reprogrammed at add the official HD functionality. Some have left the APIM non programmed for HD. It still works just not completely factory.
Normal US models sound the horn once if you double click the lock button. This still functions. The only thing affected is the double horn honk when you exit the vehicle.
Version A7 (SD card) is the current version. Every year around Jan 1 then release an update, next one will be A8. This is for MFT units (2015). 2016 models have SYNC3 and do not use SD card mapping. It is built into the unit. They have yet to release a map update for SYNC3 and it hasn't...
Most states have laws that say you can't have more than 4 forward facing lights used use for "seeing" therefore they kill the fogs. Many cars leave the lows on with the highs. I don't have a mustang so not sure if this is the case with them.