I gave a set of rotors from my D44 to my girlfriend's friend. They were fine when I pulled them, but I was changing to drilled rotors. When I sent them over, they were as smooth and shiny as the day they came off my K5. She has a "mechanic" who does all the work on her '86 K5, and he said they needed to be turned before he installed them, or the pads would not seat properly. I would like to say he is full of $hit, but maybe he knows something I don't. I understand that is the case for flywheels when installing new clutches. But, his line of reasoning insinuates(sp?) that one would need to have their rotors turned every time a new set of pads was put on. I think you'd be approaching minimum thickness pretty quickly if that was the case. So, clue me in, am I free to tell him he's full of shinola?