I know a lot of the 135 have. Post to the 1 series n54 section for a lot more hits. Here's a link:
http://www.1addicts.com/forums/forumdisplay.php?f=229
My biggest concern with that is where does it connect? Is it in/on the ECU? If so I'd hate for BMW service to find it. I'm afraid hey would immediately jump to the same conclusion as if you actually had a tune on the car.