Originally Posted by fun2drive
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...
Napa batteries are Excide and only cost 119.99 for the car.
From my understanding reprograming only needs to be done if you change to an AGM battery.