The Mosconi 120.4 has high level inputs so will work off speaker level inputs...

In this setup, we are running the speaker cables directly into the Mosconi 6to8 processor which converts everything into low level (RCAs) and provides a remote output. I could have easily just ran the speaker cables directly into the 120.4 amp and it would have powered up and down with the stereo.

The thing I have noticed with all BMWs is that when you open the door, lights go on, etc etc, it actually sends a small signal into the speaker wires which turns the amps on, then off again a short while later...no biggy at all but it is something I have noticed with BMWs