increasing sound insulation?

[swidd]

I got b-quiet for much cheaper than dynamat on eBay, its by most measurements the exact same material. It takes about 100 sq ft. to do the whole car. You don't have to do solid portions under the rear seat (no vibrations there). Suppose you don't have Home Depot, but dirt cheap rubberized roof insulation material will do the same job.

For heat problems, look into the A/C low pressure return line insulation mod.