I agree with him ^^^. Personally, if you already have a 11-14, I would keep what you have for the next few iterations of the S550 platform to evolve. You already have a capable car with the 13 GT.
2012 Mustang GT Premium
BLACK on BLACK 401A. A6, HIDs, Security, Rear Camera+Reverse Sensing, Remote Start, Comfort.
(Planning on CAI/Tune then I'll be good)