" That may help. But the thing is dynamat doesnt filter sounds. It deadens by means of adding mass (weight), so you may not hear a difference unless the whole car was matted. "
---what???????????? you dont need to dynamat the entire car to get great results. by doing key areas you can achieve excellant results. if the exaust is what is killing you then you can use a couple different products.
1- dynamat extreme. get a couple door kits or even a bulk pack and do under the back seat, the rear strut towers, behind the rear trunk pannels, and under the spare tire.
2- use some extreme behind the trunk pannels, and use dynamat extreme liner under rear seat and under spare tire. the extreme liner is a great material and will make a huge difference, and its non adhesive so you can remove it later if you wanted.
3- this may sound crazy, but look into owens corning style 705 material. its a 2" thick compressed fiberglass that most use in home recording studios. use underneeth the trunk mat and behind stock trunk pannels. you can try it under the seat but its gonna be a bit tricky since the material is semi rigid. the 705 is a low frequency sound absorber, and it will do wonders to kill exhaust notes. very lightweight, and cheep if you can find someone who sells it by the sheet instead of by the carton.
josh