i think they probably intend for this to be used for house paint,but maybe you could paint the inside of your car and avoid adding a lot of weight,like with dynamat or whatever. http://www.ceramicadditive.com/work.html
try this: http://www.lizardskin.com/ there is a great online review somewhere that tests all the diff brands of liners (heat, sound, weight, cost) iirc, there was a non-dynamat brand that was good and alot less $$$$
I've read that those microspheres are very easy to disperse into the air if your not very careful as you pour them. A good mask is super important to prevent inhaling them and having lung problems later in life. You don't want lung problems. Read somewhere that this is how Lizard skin is made. Basicly latex with microspheres!
the http://www.metalshield.com/ looks like it would be a great replacement for lizzard skin. made just for our purpose. I am thinking seriously of getting it. Ed ke6bnl
I used Second Skin Audio in my truck. It's not exactly back together and on the road yet though, so I can't comment on how well it works. FWIW, it was a bit cheaper than Lizardskin. Ed