I have some extra noise since I've installed my cat-back and would like to reduce some of it by placing sound dampening in the rear hatch area. I know there is Dynomat, but I'm not looking to 1 pay that much, 2 reduce vibrations, 3 add that much weight. Is there some other similar material that would give me reasonable sound reduction while not weighing so much (and hopefully be cheaper?) Thanks

 

Cheaper yes, light weight no... the whole idea about sound deadening is to add weight to change the resonant frequency of the material vibrating. Thus you have to add weight to reduce noise.

As for cheaper, the best bang-for-the-buck I've found is 3M Ruberized Undercoating. Works AWESOME for sound deadening, but I will warn you do NOT get it on anything you don't want it on, it does NOT come off.