Why would that be? Have they given you any reason? Have you specced any options that may cause a delay such as carbon trim or leather dash - this is usually why this happens.
AMG C63S Estate, AMG C63 Black Series, Porsche Cayman GT4 & Porsche 964 Carrera 2 Cabriolet
I get the impression waiting is part of the C63 experience! After they delivered mine in the wrong colour in Jan 2011, I put in my order for a replacement and did not actually get it until less than 2 weeks ago! This time delays were caused by the face lift, problems getting the red brake callipers for cars with the Performance Pack and then fitting the full leather dash and doors. This is my third C63 and they have all been worth the wait so stay patient!