You are right about the Insulation and dampening of the Vehicle, well in my vehicle 2010 Model, its roof liner was of ragazine (after that they used some fiber type material which u can see in sedans) . this ragzine had very thin layer of foam in it. I purchased JumboLon I guess 4mm and open the ragzine cover and put it inside, after that Ac cooling was improved a lot, coz most of the heat come from the rooftop and it was insulated properly so cooling was increased by 20%, still i didnt deaden the under dash area eg; firewall i hope i will do it someday
