The M3 does not come with Run-Flat tires.
It does not matter what the dealer or sales associate told you. The M3 does not have run-flats.
This misinformation seems like it just will not die, so I'm posting it as a sticky.
To credit the forum, click through one of the banners in my signature and the top of the page, or call me direct at 877.522.8473 ext 660.