Mine has a spray on type factory. Maybe do that in the doors and quarter glass areas.

Pricey, but Dynamat is a good product. I also heard good things about Lizardskin.

I didn't install anything in my el Camino and it's nice and quiet.. I don't want to be breathing in those poisonous fibers and odors that stuff is made from..

i used Cool It, ThermTec deadener foil/rubber/adhesive in rolls
better price than the others, covered from firewall back to speaker deck behind where the rear seat used to be