The BMW crank sensors work in the 84-89 3.2L and they are Bosch OEM sensors at reduced price. The part number for the BMW sensors is:
Bosch # 0.261.210.002 about $80
Pelican has them:
https://www.pelicanparts.com/More_Info/12141708619.htm?pn=12-14-1-708-619-M14&bc=c&q=0.261.210.002
The Porsche Bosch sensor # is
0.261.210.005 about $150
The only slight difference is that the BMW sensor harness is a tad longer. I've used the BMW sensors in the past with no issues other than a few dollars saved.