Yup, I is the one what done it. My extra-long dissertation got lost in one of the crashes. Here's what I remember...
Generic Dynamat costs much less than the real thing, and truly IS the same stuff. Two layers ought to do the trick.
MCMASTER MCMASTER MCMASTER!
USE A ROLLER!
USE A BLOW-DRYER!
Generic Dynamat Super is the BEST stuff to use, although it's not coming off, EVER. That's why I stuck mine to the back of basic dynamat. Easier to get it off if I ever have to.
Spraying the Dynashield around the muffler is not a bad idea. Do several light coats if you can. The stuff can get messy. I've done all the wheel wells.
I did the trunk with one layer of dynamat, one layer of dynamat super, and sprayed any areas that I missed. It helped deaden some noise I noticed when I had the back seat folded down.
Take out all the carpet, spare tire, side-pieces, etc. and start with the bare metal. Take the carpet off the back of the back seat and put a couple layers there, as well. Then put the carpet back.
I took out the front seats and carpet and did the same thing to the floorpan. Don't glue anything to the ECU case. The floor was letting a lot of road noise thru. It helps a lot.
DO THE DOORS!!! This is critical, particularly if you're going to have powerful speakers mounted there. I plan to put another layer on this summer after I get a door-ding taken out.
Above the rear wheel well there is a "cavity" behind the armrests for the back seat. Take all that out and fill the hole with "acousta-stuf". This is the foam filler you use if you build your own sub-woofer. You'd be amazed how much noise comes from there. Acousta-stuf only costs like $35 for a big 5 lb. box. Put half the box in each cavity.
What I haven't done yet that I think will do you the MOST good is Dyna-Liner. This is just a thick foam sheet with lead foil in it. This is a sound ABSORBER/BARRIER. They use it in RV's and airplanes. It ain't cheap, but the numbers on it are really good.
Remember that dynamat is not a sound barrier or absorber, it is a vibration damper for sheet metal. Dynamat Super has a foil backing that helps serve as a barrier. Dyna-Liner absorbs and blocks.
Every little bit helps. Basic Dynamat is the best first step, and it may be enough to satisfy you. I'm obsessive and made a bunch of mistakes at first. Now I hear a lot of wind noise I never noticed before because it was drowned out by road noise.
Hope this helps. Good luck.