I bought my 02 GT with 27k miles on it in 2004 for $16k all said and done (it was $15k + TTL, etc). IF i sold my car now that is has 56k miles on it, i'd imagine i wouldn't get a dollar over $12,000. And i think i'd be lucky to get that.
Seriously, as much as its nice to think its worth more....our 02 GTs are about $11k atm. I'd consider paying $12k for yours IF you had a lot less mileage. Not taht im in the market for an 02 GT though
Goodluck selling man.
And if you decide to Trade-In, dont expect more than like $8k from the dealer....