[ron123]

This is what I have done in the past and usually goes well ...
Took the car in for appraisals at a few places:
e.g. Carmax, Auctions Direct, new car Dealers, and Large used car lots

Some of them will give an appraisal printed out and it shows how many days the appraisal value is guaranteed for, good for a certain number of days (e.g. appraisal amount good for 10 days from the appraisal date).

Next, called up car dealers around the region and ask them if they will likely match an existing written appraisal I have on my car if I were to purchase a vehicle from them. If highest appraisal was from Carmax, I would be specific and ask the dealer if they could match that appraisal. When I found a dealer that said they can likely match, then I write down that person's name. And tell them will be back in touch when I decide on what new car I want to purchase.

In the final step I search for the exact new car I want, find special discounts, internet pricing, get owner loyalty discount from Chevy or GM, private offer discount, etc. . Then work with the dealer on the final out the door price.
I do not reveal that I want to trade-in a car when doing this step ... if salesperson asks about a trade I just say I am only concentrating now on finding a new vehicle.

Only after the final price on the new car is agreed on - then I tell them that the dealership agreed to honor the appraisal amount I have from another place on a car I decided to trade-in (and give them the contact name at his own dealership that said they would honor it).
In some states the trade-in value is subtracted off the price of the new car prior to tax being calculated so it can easily save $500 in taxes doing the trade-in option.

Another thing the salesman asks when negotiating on the new car price is if I am going to take out a loan through them. I always say maybe. The reason I do not reveal direction I will be going is that they do get some income from loans they arrange to be issued and are more eager to deal when they think they can arrange the financing.
After all prices are locked in and they ask if I want to speak with finance guy, then I tell them not interested in financing.
Ron

p.s. back at the step of negotiating the new vehicle price, if there are dealer add-ons such as: Nitrogen in the tires, deluxe floor mats, window tint, interior spray protection, tunk mat, exterior spray protection etc. (often adds $1000) I ask that those items be removed from the vehicle or if they refuse then offer them maybe $150 for that stuff.