Originally Posted by ctuna
There seems to be a vague notion on the 06's
That they may not actually need or accept registration.
Pretty much everything after that does need registration
You are correct. It is not just a vague notion. In the 2006 E90s, the ECU programming is a different version (see the Bentley manual) than the models that follow. I have a 2006 325xi and tried repeatedly to register a new battery, without success even when using INPA. I did enough research to discover that only the early cars do not have to (nor can they) be registered. The newer cars do need to have the battery be registered for the reasons that have been given.
If anyone has evidence that this is not the case, I would like to hear from them.