Apparently these are rear Cross Drilled Rotors for a 993 Turbo. Please double check the part number and verify you can use them. Originally some jackass sold em to me for my 86 951 and they werent even close. So heres a link with pics and diagram of the rotors.

http://forums.pelicanparts.com/showthread.php?t=366331

 

what is their thicknesses, at the friction surfaces? Is there much lip to them? A close up image of these areas would be great.