Aha,
So to summarize, to upgrade the WM one can use
Brake disk set 1906300 (⌀ 300mm, 25mm ventilated )
Brake Calliper Perrot left/right 99465472/3
Brake pads 59.12 / 40.10WM 1906183
Hauptbremszylinder/Bremskraftverstärker 60188878
OR
Brake disks 1904539 AM from Iveco 59.12 (these are single piece (hub + disc), for a 4x2, so this might be a problem??)
Mercedes G-Klasse calipers
Brake pads 59.12 / 40.10WM 1906183
Hauptbremszylinder/Bremskraftverstärker 99463713
I want to go for the first option, but since the topic starter was talking about a Daily from '91, wanted to be sure it fits the WM