Originally Posted by rh71

I just asked my local garage here who's familiar with BMWs about registering my battery and they can do it for $45, but they said the battery must be bought through a dealer. I can't recall exactly the reason he mentioned but it had to do with MY2008s and onward - their batteries use 4.8(something) and not 4.0(something). He said we can't and shouldn't go to Interstate directly for those.

Aside from the possibility that he's in bed with dealers (doubt it), could there be any truth to this? He has an E46 M3 and mentioned that he dealt with 4 battery replacements before realizing he couldn't get batteries from outside.