The sound mat between rear seat and engine bay was failing-meaning the foam was no longer being foam after so many years, so removed them. Took about 1 hour to peel, vacuum and peel some more. Bought replacement pads. One claim it is OEM part but it was not stiff and rubbery like the original I had, the other one, I bought Dynamat clone with silver lining. I wanted to muffle as much as possible since lately I do long drive to city once a month or so. Thus layered those two pads and 3M-ed onto the engine bay. New pads did eliminate high-pitched engine sound and some mechanical noise but not as much as I hoped for. $40X2=$80