In addition to Dynamat, try:
http://www.mcmaster.com/
and
http://www.b-quiet.com/
It looks like b-quiet is cheaper than Dynamat (price wise) and McMaster-Carr is way way cheaper. I picked up a bunch of stuff from them, including 5 gallons of sound deadening paint.
Uhhh - Mechanical work first - then the exterior - then the interior - and if ya gots any hair left, then worry about the sound.
James
I'm on step 3 of my 12 Step Porsche program. What happends when I'm done?