I am in the process of putting RAAMmat and Ensolite into my car. I got the entire trunk completely done. I am going to order another roll for the rest of the car. As I was working on the passenger side, I noticed that the C-Pillar is completely hollow. Would putting expanding foam sealer, like Great Stuff, help quiet down the car and make it less resonant as well? Any other benefits or drawbacks?

 

if you're going towards raammat, talk to rick (raamaudio).. he's done extensive sound deadening in a tC before, including foam injection

Great Stuff is more of an insulation i think and not specifically made for sound deadening.. rick would know the proper stuff to use that would do a better job.