No signs of loss of power so far. It was really weird, I went out to go visit my girlfriend and the car was off for maybe 2 hrs, start my car up drive home no sounds no problems, then when I get home (about 5-10 mins drive) as I'm pulling into the garage I heard it from within the car. I stopped and put the car into neutral still heard it so I put the car in park opened the hood and got out and heard it from under the hood and took a video of it. I shut the car off after and started it up again and listened and didn't hear it again atleast at that moment. Since then I think I heard it once under load but I'm not sure. Hard to hear thanks to the exhaust >.<. After that I haven't heard it since.
2011 V6 Black Mustang Automatic: Magnaflow Competition Series Cat-Back Exhaust, Airaid Cold Air Intake, Raxiom Smoked Projector Headlights, Raxiom Smoked Aero Tail Lights, 93H-R3.1 Bama tune, BBK Long Tube Headers, BBK Catted X Pipe