It will all depend what speakers you run.
At the time, I was using Rainbow front components which were rated for a slightly lower hz so my crossovers were as follows, all on 24dB butterworth
Fronts 140Hz - 20kHz (Drivers +1.25dB / Pass +1.75dB)
Rears 150Hz - 20kHz (both +0.75dB)
Centre 180Hz - 20kHz ( -5.0 dB)
Under Seat 60Hz - 140Hz (both + 2.5dB)
Boot 10" Sub 20Hz - 70Hz (-2.75dB)
Obviously if you aren't running the sub in the boot just run the under seats down to 20Hz.
Each channel was also heavily equalised based on my speakers and also time aligned.
Worth having a look at this thread as a lot of the research and settings will be the same as the 7CH version
https://f30.bimmerpost.com/forums/sh....php?t=1182351