51 47 ... Removing and installing/replacing left or right underbody paneling
WARNING: This page is about a different car, the 2005 BMW 645Ci and 2004 BMW 645Ci. However, it is still accessible from the selected car via links, so may be relevant.
Unscrew nuts (1).
Unfasten screws (2 and 3).
Remove underbody paneling (4) towards bottom.
Fig 1: Removing And Installing/Replacing Left Or Right Underbody Paneling