2.0 Grinding Outer Shell And Structure
WARNING: This page is about a different car, the 2013 BMW X5 M, 2012 BMW X5 M, 2011 BMW X5 M, and 2010 BMW X5 M. However, it is still accessible from the selected car via links, so may be relevant.
Always replace abrasives which have already been used to treat aluminum (risk of corrosion).
Do not grind the material thin.