This is straight out of the March N.A.D.A. Offical Used Car Guide
trade in - loan - clean retail
Coupe 2D 6 speed $15,225 $13,725 $17,800
Coupe 2D Limited $17,775 $16,000 $20,650
Coupe 2D SRT-6 $22,575 $20,325 $26,200
add theft recovery system $100 $100 $125
ded w/o AT (ex. base coupe) $675 $675 $ 675

Clean retail on 2004 Coupe with AT $18,650
This is the "Black Book" the dealers use to appraise your trade in.