Quieter exhaust in interior help

Hello Everyone,
I recently upgraded my stock exhaust to a Invidia N1 cat back system. I love the sound, but inside the car it can get a little obnoxious. I'm looking for some tips on how to deaden the sound somewhat just for the cab. I was thinking maybe lining the trunk area with undercoat or something akin to that, but open to ideas.
Any help would be appreciated.
Thanks everyone!