I used this stuff ...click...

Its not very thick but works well. with one roll I was able to do the
...roof...
...fire wall...
...small area behind tank...
...a few left over strips in the doors...

then a jute pad and abs firewall cover from classic parts.
...click...

..jute pad for floor...

...then rubber floor mat...

Im happy with the results, I dont have a sound system, and that product above may not be good for that.
I still get enough of that old pick up sound I remember as a kid.