I’d like to fit Osram night breakers to my Z3 too. ( fitted some to my old MK1 Renault Trafic campervan and it was a night and day difference! )Common issue especially if you drive a daily with modern LED headlights.
You can just change the lamps no need to change the whole headlight. Osram Night breakers are often recommended on here.
Also, don't trust RealOEM for this. Mine are actually HB3 and HB4 but RealOEM reckon the low beam is an H7.Just take them out and check. Different ages of car had different bulbs