Best Sound Deadening Material

[RetroPug]

If you have a look in my project thread I used silent coat to weight the panels to deaden them and then for insulating material I used novostrat gold which is laminate flooring underlay. It is rated to the same db reduction as silent coat (although these ratings might be dubious anyway), it is also very light and was about 22 pounds on ebay for a giant roll that will probably do 2 cars.

Also it is gold and shiny.