Very difficult to compare car deals.
Even if you think you got a good deal, someon else got a much better one.
It comes down to supply and demand. Good price on a BMW means the dealer needs to unload inventory. A bad deal means the dealer is not in a hurry to sell and will wait for better offers.
The cheaper you pay, the older the car and less desirable in most cases.
I would not fret over a couple grand. Most folks lose ten of thousands of dollars buying/selling a home.
2008 X6 xDrive 3.5