I'm using the ATR3350 on my gopro 3 black in my M3. I picked it up after finding this thread. I mounted the mic on the license plate holder like most others here. Can't beat it for around $25(factor in the cost of the microphone cable adapter).
Here is my comparison video from COTA last weekend with gopro 3 black internal mic and then with the ATR3350. I've found that the gopro isn't that bad out of the housing as well as if your car is a little louder. My M3 is stock: