You don't always need a new abs module some people can get away with it some can't the abs modules are really finicky sometimes . You're gonna need a 11-12 PCM if you don't want select a shift and a 13-14 PCM if you do . Select a shift is a waste of time in my opinion
You don't have to have the specific PCM for either. The firmware inside is what enables the selectshift, not the hardware.
BR3A-12B684-AC for any manual mustang GT or GT500
BR3A-12B684-CC for any Automatic GT (may can be used on GT500).
The firmware (calibration and o/s) can be used interchangeably between pcm hardware types. Meaning I can load 13/14 firmware with select shift on a 2011 Auto PCM.