I believe there is another thread on this subject. In the end I think it was concluded that the clutch is making the tappet noise during shutdown. There are no Tappets on this car.
If you get a chance before shutting down the car or when ever you hear the tapping sounds, just depress the clutch pedal and that should make it go away. This tapping sound usually occurs during shut down not startup, maybe you have a new noise issue?