I haven't gotten to the rear bolts quite yet, but for the fronts, there are those four large m16 pinch bolts. Mine are very corroded. BMW wants over $25 each and they look to be no longer available for the most part. There's a few sites that say they have them but then you order them and they of course don't. They are M16 x 1.50 x 65mm. I found these at bolt depot, grade 10.9, same thing. They don't have it with the flange, but add a washer anyway. All four for just a little more than half the cost of one bolt.
Bolt:
https://boltdepot.com/Product-Details?product=15201
Washer:
https://boltdepot.com/Product-Details?product=7746
I will check for those 2 part numbers after work.