To completely replace the mirror you need the following:
1) New Housing, which includes all the interior guts like the motor
2) New mirror glass
3) New turn signal
4) New repainted mirror cover
5) 3 bolts to hold the housing to the car
6) 2 screws to hold the turn signal
All in with tax and a 20% discount I got it from my local dealer for $319. I had to go to a dealer in person since the 2015 part guides are not available online (I have no idea why though). I found a 2015 Crystal White Pearl GT w/tech on their lot and gave him that VIN so I could make sure I was getting the right setup (w/ heat and blind spot).
Unfortunately you need to buy the complete set as the glass is slightly different, the turn signal is new, and even the way it's mounted to the car is changed. The old style mirrors had 3 screws coming out of the housing that you fastened to the body with 3 nuts. The new style has 3 bolts that go into the housing.
I've tried to go the warranty route but I've already had the mirror replaced once (but it was the old style unit) and both local dealers said that there is nothing more than can do as no new TSBs have come out besides what I've already had done to my car. With the amount of driving I do, and at highway speeds which make it more noticeable, the vibration is driving me insane. Enough so that I'm willing to just buy the new units myself in order to fix it.