Here's an ultra easy way to deaden your car...Everyone has heard about the spray sound deadener...Basically, out of all the stuff I've used it works the best, easiest to apply (if you spray it) and gets into all the little nooks and crannys that mat will never get to. BUT it is fairly expensive...20-25 buck a quart...last car I did with it I used 12 quarts. Here's the cool part, that stuff is nothing but a colored autobody product called "body shutz"...body shutz is around 10.00 a quart.
The only draw back to the stuff is you have to mask off anything you don't want it to get on (once it hardens it's HARD) and you have to let the car sit for 24 hours after spraying....but you can put on as much as you want...more coats = less resonance.
It sure beats cutting and sticking for hours! Looks nice when dry as well ( a textured black finish) ust a little info from an old pro who's done it all....Guty the interior and spray away!