I just successfully upgraded my Mac Mini 3,1 (Early 2009) to the BCM943224PCIEBT from a Unibody MacBook A1278 and everything works swimmingly on macOS Sierra 10.12.
As an Apple Certified Mac Technician, I can tell you that this has by far been the most challenging replacement I have ever done.
There are two hurdles to overcome. First is that the MacBook card is shorter, second is that the uFL connector from the antennas are slightly shorter than the connection on the new board, so I had to really jerry-rig it in there with a bunch of electrical tape.
I will be posting a write up sometime soon, and will update you when its done. In the meantime, go buy the card from eBay for $5 https://is.gd/PxYlLt
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