Hello Bill, Go to the Edmunds websight and enter as much info about this car as you can and Edmunds will give an idea as to trade-in, private party, and dealer retails, as well as certified retails. The "pricing experts" (i.e. Jeff) pull the BS out of their sphencter's...."55max"....Edmunds lists the 2000M5 at 61K trade in, 65K private party, and up to 71K certified. Depending upon color,condition,and zip-code the price will vary. 31K is not too many miles if the miles were freeway and the records indicate good maint. Kelly-Blue Book has a website...Knowledge is better than BS... Good-Luck Steve F.