Seems to be common that people get MAS errors on BMW and other cars from K&N oil as I read in forum for our pilot. Here in Arizona lots of dust, so I'll keep OEM. FYI: I removed the K&N in my Honda after reading all the posts about K&N not cleaning air as well as paper OEM filters.
Explains why K&N gives million mile warranty on the filter. They know your engine wont last that long with a K&N in it.