I bought an E53 3.0 for my wife just recently. The sticker was 50,250 and I got the paid 44,300 not including tax title and license. It was under the invoice according to the pricing sheet which was posted in this thread earlier. Looking back I probably could have gotten a bit more off the price, but in the end of the day, I really liked the options and color combo so I did not want to pass it up (and it was a local dealer so I did not have to travel!!)

What is the sticker price on the car?

My recommendation to you is if you offer a fair price (below invoice) on the car the dealer will take it. If you are simplying buying the car for a good deal, then low ball an offer and see what the dealer responds with, but as someone noted earlier, you may have to pass up the car if you want go too low with your offer

Not sure if this helps, but I thought I would tell my story just so you have some point of reference