I have a similar issue, my 2003 slk32 amg with 45k miles on it has a supercharger clutch that appears worn just like the op shows but no wear on the shaft, just on the surface area, i noticed this while removing it to upgrade to the eurocharged smaller pulley, should i be concerned about this? replace the clutch? or smooth out the surface of the clutch somehow? or don't touch it at all, thanks.