BMW uses two battery suppliers
Bosch who makes batteries under the Excide name
Douglas is the other battery supplier
I think as long as you stay within the AH requirements give or take a few amp-hours you will be fine. You can register your battery with a K+CAN OBDII cable and the software our generous poster provided in the coding section of this forum
After this you should be all set. If you get a huge difference in AH rating you need coding but stay with in reason say less than 10% my guess is you will be fine...