New carpet problem- mass backing issue

Its actually a used "alternative" for Dynamat. Saw it in a few Dynamat/Fatmat threads. It com in 6" x 25' strips for $15. I have 4 rolls sitting in the trunk.
Im gonna start a new thread to get some feedback on it. Ive read the old ones and it seems as tho the jury is still out...

I like the fact that it should help with the heat/noise but my main concern is the extreme heat in FLA and possible melting/smell that could result in use.