Rain,
That "that round gizmo with all those metal tubes sticking out from it" is the old CIS module.
I don't think it's so much a case of the airbox having 'extensions' as it is that the center part of the airbox has been 'notched out', if you will, to accomodate the CIS.
It's tough to tell because of the different perspectives in the pics, but i suspect that the differences in the AMG box are largely internal.
though, to be entirely honest, aside from the spiffy AMG lettering on the airbox "I can't see a difference. Can you see a difference?"
