As we all know we drive turbocharged pepsi cans. Road noise and vibrations were driving me nuts so I had dynamat put down on the entire floor of the car. They took out all my interior and placed it down on the entire floor. The car is much more quiter on the freeway. I still hear my turbo and boxer rummble. The car actually "feels" more solid. When going over bumps and rough roads, it doesn't feel like the car is going to fall apart. I know its extra weight, but i think its worth it if you live in an area where most of your freeways are concrete. After i installed my springs, the ride was very rough and jarring. Its werid, the car even feels smoother even though no suspension work was done. Overall i'm very happy. If you don't mind a little extra weight. I highly recomend have it done. I would have done it myself but i just don't have the time and its just tedious and time consuming work.
Next step is to have the doors dynamated. I'll put it in when i replace my speakers, after that the trunk when i get my JL w6 with stealth box.