Dynamat / Sound insulation newbie looking for HELP!!

I own a 1990 GT that has not only been a 3 year project but a money pit........like every other persons on here isnt.. Anyway I have to pull my carpet again and am going to replace it with new this time. I want to add some sounf and heat insulating mat to the floor and trans tunnel, trunk, rear quarter sides and the roof. Which brand is best, and whats the best deal? Ive found this link and it looks pretty good... http://cgi.ebay.com/ebaymotors/ws/e...m=120265103378&ssPageName=STRK:MEWA:IT&ih=002 .. Also how much do I need to do the areas I want.? The company in the link says 100 sqft will do most any midsize car, but Im prolly not doing doors. Any particular areas to focus on or not to forget? I currently have 2 - 12's in the back and they sound great but want to make them sound better and stop hatch and roof rattle. I also have no AC so I want to cut down on floor and other radiant heat.....ALL OF YOUR INPUT IS WELCOME..Also do I have to buy this online? I will NOT buy from Best Buy that **** is wayyy to expensive there. Thx

I am NOT going to pull the dash out again. Plus there is already some of the stock sound deadner behind the dash. The door already some done by the previous owner. My main goal is trying to keep the heat from the trans and exhaust from entering the floor since I dont have AC to cool the inside. There currently is no insulation in the headliner or trunk so anything would help a little there. I think $750 would do every square inch, which would be good If I was doing bass competitions...but Im not. With this said wont the 100 sqft cover the areas Im looking to cover?

I called Dynamat Inc. and they think I need 2 - bulk boxes 36' sq feet. They suggusted that I use Dynamat extreme on everywhere I want then add the 1/2" Dynaliner to the floor and roof for heat control. I checked the price on the stuff and your right, its damn expensive. Whats the difference between the FatMAt stuff or other products? Ive heard that nothing works as good as Dynamat but thats from authorized dealers and the company itself so of coarse they are recommending it, and I know theres more than one way to do this. I will measure and do the calculations tonight on the square footage. I will do the doors but it will be the inside of the door skin and not right where the panel is mounted.