You MUST get the battery registered to he car. Either at a Indy shop or the dealer.
Get a battery wherever you please, you get what you pay for. Regardless, get it registered.
I just spent $300 at the dealer for this. My Indy wanted 300 as well so whatever, took it to the dealer. My local dealer is pretty decent. OEM batteries run about 200 bucks.
2008 328i E90 Jet Black:6MT:Premium:Sport:Walnut/Black interior:Xenon:MTEC V3 AEs:19" Beyern Mesh:35% Tint:Blacklines