WARNING: This page is about a different car, the 2013 BMW X5, 2012 BMW X5, and 2011 BMW X5. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Frame (0494126)
Courtesy of BMW OF NORTH AMERICA, INC.
NOTE:
(Side frame) Only required once for constructing the base frame Deletion, only available via tool set