Well. for some reason it didn't work on my M. I removed my firewall grommet, and installed 2 different types of "sound generators". One from a 2003 3.0, and another thats a bit smaller. I routed a pipe to go right next to my supercharger, and even tried running with no pipe coming out of the sound generator end, and no foam. Same thing, car sounds the same. Therefore:
1. The M cars have something blocking sound coming through the firewall, other than a little circular carpet type thing I removed at the hole or:
2. The drum thing inside the sound generator needs some sort of pressure or vacuum for it to work, by being directly routed into the intake. I'm not ready to potentially disrupt my airflow or lose boost by hacking up my supercharged intake.
(dirty engine bay)