Originally Posted by ADKX1
You will need to secure the butterfly valve (I suggest open position) or it will rattle like crazy! I simply used some copper wire, but solder or tack welding would be the best option. I'm not sure the BMW service shop will be too happy about you doing this and I have no idea what it does to the warranty.
Shouldn't have an issue with warranty. The ECV is used for warm-up and the valve opens at 3k RPM or higher. A lot of the 3-series guys remove the valve to increase the deepness of the exhaust.
You've decided not to mount it behind the crush bar then huh? Did you take any photos?
You must have had to remove the rear diffuser to have some room?