I have two cars with separate issues. The Firebird was sound/loud the other one was heat. I used the Hvac duct wrap( foil backed rubber )( Home Depot) to help with sound. Worked ok. Better than it was. I used Mylar bubble wrap sheets( also Home Depot) for the heat issue. Worked ok. Better than it was. Seems like most of these products address either one problem or the other but not both.