Trust me they like the ignorant part of their clientele a lot more than the 1% who knows wtf they are talking about. They can't BS us and that pisses them off to no end.
For everything I buy I always research the crap out of it and I'm generally a lot more knowledgeable than the salesperson, at least on this particular model. That's my engineering background as opposed to their sales background.
You bimmerpost sticker would serve no purpose as 99% of them don't know the existence of this forum.