Another important part to get the best deal possible is by NOT NEGOTIATING. If you feel as most of the car shoppers do that face-to-face negotiation with a car salesman is the only way to get the best bargain – thing again. Trust me never ever visit a car showroom for negotiating price, try getting it on phone or email instead.
Watch this short video https://bigthink.com/videos/how-to-buy-a-car-using-game-theory-2 of Bruce Bueno de Mesquita, author of The Predictioneer's Game, talking about the optimal method to getting the lowest price on a new car. I love the way he sums up the process in a simple to understand way.
Use the first visit to a dealership solely as a trip to look at the car and gather preliminary information on specifications. Let the dealer know that you are not buying today and that you’re simply in the research stage. Gather the information you need from your visit and leave so you can collect your thoughts on your own without someone hovering over you. Then move on to the next dealer on your list, and repeat.