I would try and sell it privately first. Your will get more for it and the person buying your car will pay less than what a dealer would sell it for. It's a pretty popular car, so I don't think you will have a hard time selling it yourself. Whatever you do, don't mention you have a trade-in until the sale price of the Z is finalized and in writing. Negotiate from below invoice and work your way up. Be prepared to leave if you don't like the price. There are also a few dealers on the forum that can get you the car below invoice, but I'm not sure if the dealerships are close to NY. Good luck!