Costco has a car buying service. My daughter used it to buy a Subaru. She told them exactly what she wanted and received a quoted price. She then went to the dealership to pick up her car, which was there and waiting for her. She met the sales manager, had no hassel and drove off with the car.
She did look at Subaru on her own, and got a run around and the dealer tried to put her in a car she clearly told them she did not want. It was a year older than she wanted with a smaller engine. The salesman even called her later and told her that was the only car he could give her. Basically he was trying to push a car that had been on the lot too long.
I don't know if going through a car buying service is the best way to get a deal, but it was hassle free and no gamesmanship.