I used the target price from carsdirect.com and subtracted about $500 off of that for my target price at which I would purchase. I also used all the dealers in about a 200 mile area to make sure I would get the best target price, it will change with different areas. Once I had my target price I emailed all of the dealers within the 200 mile area and let them know I would be purchasing the car within the weekend, this does make a huge difference! I really feel this gets the water churning, especially if it is the last couple days of the month. I ended up having a dealer in my area call before I could even get all other dealerships an email sent out saying he would meet my target price. I ended up paying $25,300 OTD for my EX auto with Nav ( my target was 23,600, I ended up paying for the $300 window vin etching, $100 dealer locate fee, and thier cost, $120, of the mud gaurds, they wouldn't budge anymore than this). If they know you are serious and are going to buy a car in a couple of days, they will deal, especially with no trade in.
Good luck with the purchase, I love my car. Everything and more than I expected.