WARNING: This page is about a different car, the 2015 Audi RS 5, 2014 Audi RS 5, and 2013 Audi RS 5. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Engine Cover (4.2L Engine)
Courtesy of AUDI OF AMERICA, LLC
-- Carefully pull the engine cover out of the retaining clips one after the other -arrows-. Do not remove the engine cover on one side or in a jerking manner.