this past weekend I replaced the crumbling, original sound pad in my 79SC. I searched the forum for thoughts on whether to use the OEM replacement (much lighter than the original) or the foil one. The foil pad weighs less than a pound, but costs maybe 20 percent more than the OEM. I opted for the foil version.
Since my original pad was hanging off, I can't say whether the sound attenuation is any better with the new pad, and I don't ride in the back seat,s o I can't say if the insulation characteristics are any better with the new one. What I can say is that the foil pad helps enormously by providing a light reflecting surface at the back of the engine compartment, making working on the engine a lot easier. Anything that does that for me is a big plus in my book!
Just wanted to give some feedback for future reference!
Matt