These are the links for the Adobe Illustrator Plug-Ins. I will try to update them when I can, but if you are having trouble let me know.
Windows Plug-in HERE.
Mac OSX 10.4-10.7 (Lion) Plug-in HERE.
Mac OSX 10.2-10.3 Plug-in HERE.
I have tested (honestly) to see if past models specs work with the Silhouette Cameo but no such luck. Thankfully it is still possible to export the file (as a .dxf) to import to Sihouette Studio!
To install the correct drivers for your machine:
Select CC200-20 for Silhouette Machine.
Select CC300-20 for SIlhouette SD Machine.