Thanks for the strategy you used,everything done online sounds too be the secret
I know the bidding war strategy works well for many; however, I got what I consider an excellent price on what will be my first BMW by working with one dealer.
I first did my pricing research online using this post as a guide:
http://www.bimmerfest.com/forums/showthread.php?t=916818
After I wrapped my head around the pricing aspect, my next area of research was local dealers as I had no clue who to use. I first tried using the closest one; however, I didn't care for my CA and felt the dealership was not very honest. I then decided to do a lot of searching on the forums to find feedback on my local dealers, read online reviews, talked with other BMW owners that I know in the area, and then I picked a local dealer that had a good reputation for a second try. Let me say, finding the right dealer is very important, as it was a completely different experience compared to the first dealer.
Using the pricing calculations I configured my car, calculated the invoice vs MSRP pricing, and then contacted the dealer I picked. When discussing pricing with the dealer, I was open and honest with how I got my numbers. We used my calculations as a starting point for negotiations and then went back and forth a few times. I was able to get below invoice (per the calculations) on a 2018 order plus apply my applicable incentives. If I calculate my percentage off MSRP, it is much higher than 5%. In the end, it was a smooth process and I believe both parties were happy. I got a very good price, and my dealer knows that they have a satisfied customer who will use their dealership for service and potentially a future BWM purchase.
I know there are many different strategies out there for how to negotiate, and each person tends to prefer one. My suggestion is to educate yourself as much as possible on the pricing before you do anything. Then how you use that information depends on your preferred strategy. I don't like to contact many dealerships and get them into bidding wars, as I believe this takes a lot of time and doesn't necessarily get you the best price. That being said, some people swear by this strategy, and if works for them, awesome.
If you have had a bad experience with a dealer (which it sounds like you have as I have followed your story throughout the forums) then I would suggest trying another dealer. But before doing that, I would do some research on your local dealerships and pricing if you have not done so. Being well informed and working with a good dealership is very important to getting the best price.
I don't claim to be a pricing expert, but thought I would share my experience, as I am very happy with my experience to date. Now all I have to do is wait for my 2018 to show up.

Good luck!