No one has said a word, so I found a way to answer my own questions without traveling. Here are the facts:
A - the holes for the bolts are the same diameter in both wheels.
B - the taper of the lug bolts is 60 degrees for both the 12mm and the 14mm. This is what actually clamps the wheel to the hub.
So, those wheels fit my M3 using the OEM 12mm bolts. I have purchased them cheap ($150 a set of 4, they look like new), mounted new winter tires and will install them in the car. They are heavier than ideal since the wheels are 26 lb each. But they are strong and now I have a non-staggered winter set-up (245-40 18R). I intend to carry one of the same size summer front tires in the trunk, in case I have a flat.
