a need for deadening?

[Souldriver]

So right now nothing shakes in my car (nothing that shouldnt shake) with volume turned up on the shaker 500. But i know on my old car the windows shook bc they were frameless and it was a big annoyance.
With these 2005+ mustangs is there and iduue with that stuff? Or is it more to keep the speakers sounding better and isolated.