Well, i bought the car all sound deadened but compared to my old hlx its quieter but if you want to do it to make it quieter then dont waste your money!!! only worth doing if you primarily dont want the car rattling all over the place!
I would recommend doing it though as it does make your car slightly quieter, the sound system sounds better as you dont just listen to rattles! and the car feels more expensive! as the doors and everything feel heavier and feel more like a bmw then fiat! and when you tap the side of the car it sounds like a tank instead of a car!lol...
Paul R