Don't trust anyone. You won't be there to see what happens during the demo drives with the customers.
For example, when I was shopping for an M3, I test drove a few times.....And I pushed it to redline almost once during each test drive. The salesperson got upset, but I still revved it and unfortunately you can't go back in time and reverse the fact that it happened. I know I didn't do the right thing, but the point I'm trying to make is that the 6% discount is not worth it since test drivers will probably still redline it every now and then.
One question: Can't you negotiate the 6% discount off of the MSRP anyways?