BTDT. The 8.1 is so loud to begin with I didn't notice any increase in living room noise from behind the driver seat while driving.
On the other hand the new flooring is gorgeous and the wife loves it.
Adding half inch sticky back engine compartment sound proofing, from West Marine, to the underside of the doghouse did reduce on the road noise and heat transfer.
BTW: same material worked great on the generator box walls.
Jan and Rocky
Volunteers USFWS. 9,300 hrs each, 29 refuges. 04 Allegro 30DA, WH 8.1, Banks, 2012 Jeep Liberty , Brake Buddy Adv Select, 300watts Solar,
"Philippians 4:11-13 KJV"