I just did this mainly to lower in-cabin noise. I did the doors and trunk. The doors have a nice thunk to them now. I figured I'd replace the front speakers while I was in there.
Here is what I used:
-1 roll of raammat
-3 yards of ensolite
-1 can of spray adhesive
-2'x4' of perforated aluminum (this covered two holes in the rear doors, three holes in the front doors, and two holes in the trunk. I zipped them in with self tapping metal screws.)
-1 set of 6.5" Front Adapter Rings from IA Performance
-Focal 165 V2 slims
-tin snips for the perf aluminum
I guess the only notes I have are that the resonance in the front door are mainly near the bottom, and more than two layers of mat inside the door are a waste. Also, you should only need foam behind the speaker inside the door. There is really no reason to have foam anywhere else inside the door. I matted the whole trunk, which is probably a waste. If I did it again, I would just mat the resonant areas, the wheel wells, and foam the whole trunk. I found the easiest way to apply the mat was to peel back a small strip to position it inside the door, then peel back the rest when it was in place.
This was the first time I have done anything like this and it was WAY easier than I thought. I already told a buddy I would help him with his car. He was very impressed with the improvement in my car.