Meh, I still can't tell the difference between Fatmat and Damplifer besides what is easier to put on.
And I have both in my Focus and 1 layer of each in my trunk, just some in damp and others in fatmat. Actually ran out of damp and didn't get to the important areas and put the fatmat in there and works fine and still there well over a year later.
I can't hate on fatmat, has done fine in my case. I did double up the doors on the fatmat through. And went verticle with it, which is a hugeeeeeeee no-no, lol! Still there doing what it is supposed to do.