For kmarei, or anyone else looking for replacement parts, we have Tire Rack part # KITBERU. It is a rebuild/installation kit for the Beru (company that makes BMW TPMS) valve, so it includes a couple of washers, a replacement gasket and I believe a valve core also. They run $4.50 per kit plus delivery.
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.