We agreed on a price prior to ordering relative to the invoice price. The dealer did not want to agree to a fixed price because the cost does not always stay the same throughout the model year - it often increases. I agreed to pay the dealer $100 over invoice price in effect on day of delivery. I'm pretty sure I could have got down to invoice price but I was pressed for time and tiring of dealer BS.
The invoice price did increase by about $100 during the time between my order and delivery date (almost 4 months); however, I was given a $500 rebate on delivery date that was not in effect on the order date.
If you order you may want to consider going through your dealer's internet rep. Some X owners have reported smooth transactions by doing so. I went through a salesman, and had to endure the usual gamesmanship.
Also, refuse to pay any unwarranted fees such as documentation or advertising. Only pay for the vehicle, delivery, tax, title, registration, etc.
Good luck w/ your negotiations