More importantly, Why do you know the, (and I am sure I can't say it as quick as you) 1/4" visco-elastic sheet material is simular to the stuff they use on submerines hulls? You have to admit that isn't a term one hears around the pickle barrel just everday.
I just swapped my OEM pump to the Johnson this morning as well and thought about doing the same but I rigged the new mount on for mine. See, If i had some 1/4" ...
Enjoy the ride,
Mike