Originally Posted by FormerRotor
I believe that this acts as acoustic dampening, but it may also have something to do with the spring-loaded secondary air assembly in the box. Yes, the filter is installed with it on (it's glued on).
Excellent. Thanks for confirming this. So far this is the only BMW I have come across with this "glued" piece in place on the oem filter. Do you guys think it is restricting airflow?