I did the E70 X5M calipers on my E70 35D, and found I was missing something with my F15
The old setup was 4 piston monoblock. It turns out that the 6 piston newer design caliper from the F85 X5M fits the F15 and also the e70. You run the F85 395 mm x 36 mm front rotors
The rear 4 piston is from a Porsche Panamera with a custom bracket, allowing you to run the 385 mm x 24 mm rear F85 rotors.
I was waiting for a backordered protection plate, so I hope to complete the install this weekend
This thread has all the relevant technical info
https://f15.bimmerpost.com/forums/sh....php?t=1450854