[cfw]

I'm trying to add a yet-to-be determined subwoofer and amp in the trunk of my 2013 X3 (F25). I have the upgraded premium audio package on the SUV and I think it lacks bass.

1) Does anybody have a wire guide / diagram for the premium audio package? I'm most likely going to do speaker level inputs and want to get the right wires.

2) For a clean install, does anybody know what the part number is for the clip to go into this giant block on top of the battery (see attached)?

Any help would be much appreciated!