LOUD Exhaust Tamed.........
When I had the duals put on my car, the interior resonance was
annoying, to me, and it really bothered my G/F.
{I am using Dynomax Super Turbo mufflers}
I decided to add some sound deadner to the floor under the rear seat,
and the package tray areas;
heck, there wasn't even carpet padding under the back seat.
The car is much quieter inside now. :)