I don't use it on the M3 unless I'm in a long drive-thru line. I think people appreciate me not idling with exhaust fumes from the akra. It's perfect for those situations. It's on by default all the time on our X3. Doesn't bother me at all.
(1:40 @ Laguna Seca, 2:03 @ Thunderhill, 1:52 @ Infineon)