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.
I have accepted a new position at Tire Rack and am no longer in the sales department. firstname.lastname@example.org
is available to assist with M3 questions.