The secret to negotiating is that you have to convince at least one dealership to give you an estimate IN WRITING and then once you have that you can flaunt it in the face of the next dealer and have them beat it also IN WRITING and just repeat that with dealer 3, 4, and 5.
Dont be afraid to get proposals from dealers that are really far away because the more dealers you speak to the more estimates and the more likely to get a low estimate.
Also when I first started I went to Trucar website to look it up and you can take that price and drop it by 2 thousand and start your negotiations from there.
And the best secret is do 95% of your negotiations via email or telephone. You only go to the dealer twice, Once to test drive the car and then you come back a few days later to sign the deal. Thats it, the worst thing you can do is "Come on in to talk about it" because face to face they will play their psychological games with you
Oh I almost forgot, if they are dumb enough to send the estimate in pdf than you can edit the file and change it to any price you want in order to use it to fool the next dealer. It might sound "under-handed" but its no worse than the bad rules that the dealership plays by.
If you are not good at "doctoring up" documents than you can hire someone on Fiverr website to do it for you
Why even bother getting estimates, just draft up your own from the start and see if anyone will match or beat it?