Originally Posted by andrewwynn

Better yet! You already have a perfect spot for the vent. You can add a solenoid control vent and you can start with a bigger hole and add a reducing insert if it's too big.

My first test with the open flap I just unplugged the vacuum line and put a screw in it. I could manipulate the flap open/closed manually and I figured out that 3 or 4 hours is the limit before it gives me a headache. Fortunately I discovered I can perform the function with bimmerlink so I set it to auto for freeway driving and open the rest of the time.