You may be interested in the following link describing the filming of a BMW commercial involving an as yet unannounced prototype BMW. BMW also sponsors a professional Americas Cup sailing team, hence the location. The facts...
1. I used to work for the sailing team involved and presently work for one of their competitors.
2. I am not presently in Valencia Spain, otherwise I would have a photo.
3. I cannot confirm the car was an M3 yet, but it is fun to speculate and I am working on confirmation (or denial) from those who were present and involved.
If anyone is in or around Valencia Spain, there may be an M3 in your midst. Keep your TV on!!!