Watch for ad-ons that they don't mention to you at all that might be on their invoice. I had a charge for 'ETCH' added. I refused to pay it and they took it off, even though the work had been done. It was never mentioned prior to me seeing their invoice.

Aside from the typical stuff, my dealer also tried to get me to buy LoJack - I declined.

I did buy an extended warranty. If you plan to keep the car a long time, get the longest warranty available. The high-tech components are very expensive to fix when out of warranty. For just a few dollars a month, you buy a lot of piece of mind.
Good luck!