Thanks! The reason I asked because I am doing the 944 alu arms with 964 C2 2-piston calipers conversion for my 1303. I know that the 986 S rear discs will fit but I can get some used 996 rear discs for free locally. I did some research on some Porsche parts vendors' webpages such as Pelican, Paragon, etc. Their part references are different, except for those I found on EBC's website
http://www.ebcbrakesdirect.com . The EBC part numbers for the rear discs of 996, 997 and Boxster 2.7 (99-) are the same (D1065). So I just wondered if I could use the 996 rear discs for the conversion.