My 335i has this also. Its called the golf tee mod. If you pull the rubber hose off, stick a bb, or golf tee in it and it will stay open. If you remove the cover from the back of the drivers side tail light, there should be a small plug in there that is for the exhaust flap. Just remove the plug and it should stay open all the time also. THis is the safest way to do it.

What M button are we referring to? My X6M doesn't seem to have it?

The one on the steering.

Here's the pic.

http://www.xoutpost.com/members/lema.../E70-X5-19.jpg

Ok Thanks. I have an 08 vette with the dual mode exhaust and simply by removing the fuse, the baffle stays open. I wish the X6M had the same system.

If the white car in your Avitar is yours it doesn't look like an M. Looks like an X6 5.0. you have another one?

Yes, thanks; just sold the 50i and picked up a white/black X6M. The vehicle is awesome! However, I do believe the engine growl inside the cabin, not necessarily the exhaust note, was more agressive in the 50i.

JDM996CAB

Using iDrive, you can change what the M button does.

does the X5M have mid mufflers? take a peek under the car.

a more agressive exhaust will be achieved by removal of mid mufflers (or resonators). the unknown is if the sound will be agreeable to your ears!