I just had the battery replaced on my '06 Z4. It works fine. The old battery still checked good, even thought it required frequent jumps if the car was idle for several days. I will trickle charge the battery and see if I can get it back from Black to Green. Any similar experiences out there. Also what is a good cleaner for my roadster top. Its black, the car is garage kept but it could look better. Any suggestions. Thanks.