I think the whole DS issue is a hoax. The Youtube videos were created as a commercial to scare people into thinking that the stock DS will fail. If you haven't seen the videos, I recommend you to watch them. The two guys look so prepared and sure that their DS will fail, that they carry a camcorder on their shoulder to wait for that moment.
Honestly, which one in this forum (or knows a friend) has a failed stock DS? I understand that the old GT drive shaft has a very thin part in the middle with a center bearing. That part is prone to fail for sure. But for my 2014 V6, I can not tell the difference between a stock DS and the aftermarket ones except for the fact that the stock one has the sliding yoke in the middle, and the aftermarket one has it at one end.
2014 Mustang V6 3.7L 6-spd manual, with MGW shifter, Airaid CAI, BBK shorty headers, Corsa Sport axle back, strut tower brace, JLT oil separator, GT500 differential cover, BG Synchro Shift II gear oil, Redline differential oil.