I just finished doing the first phase RAAM mat application in my 04 STi, what a difference! I had already done my doors during my initial install, but had no deadening in my trunk or the rear deck/seat area.
I sealed up the rear deck with two layers of mat, and did a single layer over all of the large flat surfaces on the upper rear seat frame and wheel well. Total about 7 ft.^2 for this application. I sealed up all of the holes in the rear deck except for the two vent ports, I also used ensolite to wedge the middle seat belt bucket in place. No more rear deck vibration with trunk bass, much less tire noise off the wheels, and a little less exhaust sound. (Note: I have an amp board which already seals off the rear seat/trunk opening).
Great product! Rick was very responsive with details and advice, great guy.