Regarding the M3 mirrors. I was at my dealership this morning and the M3 coupe mirrors definitely look like they could fit my E93. I'm now going to call my service guy and see what the cost would be part and installation wise. I'll get back to this thread when I find out more.
But the mirrors look great in person, they do fold (premium option behavior) and the triangular panel the mirror is attached to has a more brilliant black coating to it, almost glossy looking as compared to our cars.