I saw the engine cover so I whipped one up to try out.
I put some foam weatherstrip on it and took some drives.
I can not tell a difference in sound (which is pretty amazing by itself).
And the weight difference is stunning.
5# for the original and 366 grams for mine, that's 13 ounces.
You can't see it and other than a little weight, it does nothing.
But I can make more...