Good point about prices on new. I've read recently that prices on new vehicles are actually better than used prices for many vehicles. This may be especially true for xfires, considering they've reached the end of their production run, and they are a low-demand vehicle.

The most important thing to do is not lose your cool. Look for cars that have been on the lot for >30 days. The longer the better. Name your price (even if it is a little ridiculous), and walk away if they don't want to meet it. If it in anyway helps them to sell the car and get it off their lot and their books, they'll be calling you in a few days. My xfire had been on the lot for 2 months when I made my offer, which was 20% off of what they were asking. It was rejected first, but a week later they called and accepted. Note this was a year ago. I'd expect if it happened today, they'd probably accept my offer on the spot.