Sorry, you got duped. There really are only a few places which make batteries. They're all (essentially) the same as long as the specs match up.Damn,
I bought a battery from autozone but when I went to the dealership and talked to them they told me that the quality there is bad and that for an M3 you need their battery because it lasts longer. So I bought there's for about 250$ but they wanted another 150 for installation so I said **** it and put it in myself.
Geez i'm such a chump.