One problem related to wiper has been reported for the 2003 BMW Z4. The most recently reported issues are listed below.
Vehicle windshield wiper drive failed catastrophically during a severe rainstorm while vehicle was traveling in inside lane at 65 mph in moderate traffic conditions on I-65 at lee st. I was very fortunate to get the vehicle off the interstate without crashing. Note: drive motor for wipers operates passenger side with linkage to driver's side. No indication prior to failure. Drivers side bearing failed allowing linkage to drop from driver's side wiper pin. Design should be modified to drive the drivers side rather than the passenger side or linkage modified to allow gravity to secure the linkage to the driver's side drive pin.