Scottyboi - I have the big qtr panels lined with 4mm deadening leading into the pillars then topped with 8mm sound proofing. I have 4mm deadening on the floor of the car, just need to do the passenger and drivers side footwell's.
Then when I have settled with the equipment, i will line the boot space area with more deadening, not doing the roof as its packed out.
I currently have a 1krms sub running and on high volume 55 out of 62, no panel rattle apart from the exhaust sheild....