Took my 02 Z3 in since the subwoofer was blown (still under warranty) and asked them to replace it with the Sunfire unit (there are still 36 in the Cali warehouse apparently). My service guy contacted BMW's warranty department, and they said he couldn't do it even if I paid the difference in cost. They said it can only be replaced with the factory unit that was in the car to start with. Anybody know any way I can get around this? Thanks in advance.