I'd say before you go dynomat happy on the car, install the system, and turn it up. Try and locate the rattles, and then go from there. I'd bet you will be surprised on how little dynomat you really need. I have NO dynomat in my car, i have a 15" sub with over 2000 watts to it, it pounds like hell, and don't really notice any rattles except my radar detector bouncin and buzzing. The rear hatch cover rattles a little too. Sometimes most of the noise is made by 2 plastic panels vibrating on eachother, and just by sticking something behind them will cure the rattle. Dynomat work very well mostly on metal panels of the car, to help those not to vibrate. The spray stuff works well on the rough spots of the car, and inside the door panels where its hard to get the dynomat to go..

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)