I have, my car between KBB and NADA says ~$19k trade in. One dealer offered me $17k, which goes to show you they don't really care what KBB/NADA say. I know I don't have sport or touring, but its not like my Z is a rustbucket. I also have it for sale privately and someone just offered me $15,500.
Sad how bad the resale value is on these cars. I just did one of the auto-trader trade in forms. I am planning to take that to a dealer that has a car I want and see how that works, or if they'll just buy it for what it says.