I price a car based on its marketability and nothing more. I have to get it for less than I know another guy would buy it for simply for the fact that as the world changes, you want your investment to be as liquid as possible. That said, I will always pay a premium for originality and completeness. Service records and ownership history are major bonuses. While I am a great amateur mechanic, not all are and I hate nothing more than to end up with the previous guy's hack job.