Sound deadening
Sound-deadening is vital for good performance of the system, There is still plenty
of deadening to be done on my car - I want to mat the roof, and pad the floor to damp
road noise... But this is what I've done so far....

The Rear Wings

The problem here was that the sub made the whole boot area rattle and shake like hell, So
basically I filled the cavities with expanding foam, This would brace the panels and prevent
vibration.  It certainly has made a great difference.
The only thing is that if you are not carefull the foam could push the panels out as it expands, so build it up in layers, and take your time...

The Doors
The doors were sprayed with rubberised underseal and then matted.

The Underseal