I am in SoCal.
I used CostCo just as a starting point to see where I should start my negotiations.
When did you get your price quote? Was it after 6/1 or before? Have you identified the largest dealers near you?
The most recent quote was as of yesterday. You're already ahead with auto buying programs like costco because you're starting at "invoice" or a smidge below (about $800-$900 off already), stack this with 1-2 incentives and you should be at or nearing 2k. I'm still new to this but being part of the club gave me a good head start. Get 2-3 dealers competing with each other and you should achieve a good discount. I'm in the NY tristate and I am literally conversing with a dealer in each of the three states.
Note: Before I even started this process I read through much of the lit James Bragg posted about the auto industry. It was pretty eye opening especially his bit on sites like Truecar and their allegiance to the auto industry and not consumers.Check out his 5 part series or skim his other articles. http://clark.com/voices/james-bragg/