[DanEC]

ERAs have aluminum floor pans so it's not quite as difficult for us. I coated mine with several coats of ceramic based Lizard Skin on the underside. And then on the top side I used a thin mastic damper-proofing and a double sided insulation layer by EZ Cool. With fiberglass floors I think I would apply something like the Lizard Skin material but also use a metal or aluminum heat shield between the muffler and floor. I'm also ceramic coating my head pipes and mufflers which I hope will knock a few degrees off of their external temperature when the car is running.