Edmunds tends to low-ball with their TMV program. For a realistic value, pull from:
http://www.kbb.com
http://www.edmunds.com
http://www.nadaguides.com/
Average the value across the highest two.
Private party, good condition example:
1990 Turbo, Gunmetal, 225K miles|
NADA:|$3,600
KBB:|$2,815...