when i was looking for my z06 i came across a 03 DSG all stock with 9k miles on it original owner going for 21k firm. that was a good deal to me as well, cars such a good deal right now.
when i bought my 2nd terminator i paid 25k, and it had 5k miles on it. This was in 05, some people buy them and think they will gain value over time, but then find out they actually loose value. the Shelby GT500 might hold its value due to it being a (SHELBY) but most people go off of blue book value. clean car though