I've been using the Z3 so much over the Christmas holidays that the M3 came up with a "Battery Charge Low" message after driving it yesterday. The Z is really getting quite a bit of attention and the newer car is showing its jealousy.
I wanted to move my Z out of the garage on Saturday afternoon after work to have a sweep up as windy weather means dust, leaves etc. gets blown in. Press button to unlock, not today thank you, battery flat as a (you can guess). Luckily for Christmas I got a new battery starter/charger so it has been tested for the first time.