Originally Posted by ben1364
...I don't think much of the idea of diddling with airflow based on heresay.
What else do you have to go by?
There's a lot of good hearsay here.
It's got to increase air flow and I believe the article said the filter is not on European models.
I don't know if the charcoal filter is on the E90?
I have 2 questions:
1. Would this void the warranty?
2. Do you think your BMW dealer would do this for you?