According to a study by AMG a very miniscual ammount of people are inrested in purchasing AMG products in general with a manual transmission.. if I remmber correctly it was about 5% that was intrested.. for these reasons AMG never opted to use a manual transmission, but either way no manual tranny amg was ever made since the first mercedes-amg production car c36... not even the DTM.. I am not sure about the GTR though..