brutus

With so many early cars selling for less than $5,000 some far less. That is a lot of money for anything less than a near perfect car with good documentation to verify miles. I would also think you need to drive it or one like it to see if you LIKE it. The USA 16 valve car especially in an automatic is not much of a thrill ride. I talked to a guy with a GT3 this weekend he has a 79 928 5 speed he bought in 1982, and an 88 5sp S-4 bought in 1990. 79 has not run for ten years, 88 needs a head gasket. He said now that he has the GT3 he has no interest in fixing the 1979! Might get around to the S-4 someday.
So much depends on WHY a person wants a 928 and what their expectations are. Also what you compare them to. As an investment for appreciation potential the 928 is a bit too much of a cult car with a reputation somewhat deservably of being expensive to fix. There is no big demand for them. There is a reason some people have several, because they think they are worth more than what the market value actually is and happily buy them.