I have an 09 M3, E92. P/S fluid cap also says CHF 115 fluid.
I used to change the P/S fluid via the turkey baster DIY method in my e46. I assume that also goes for an E9x?
(Turkey Baster DIY: Suck all P/S fluid of the reservoir you can with a Turkey Baster. Refill reservoir with new fluid. Start car. Turn wheel lock to lock 1X. Repeat twice more.)