I have the solution to your potential noise issue...........
sell the truck to me and buy a Prius.
But really, just own that you are going to drive a wicked truck with an old diesel in it. I have been told several times over the years that people thought a old diesel transport was coming down the road with my truck. But really when driving it around the turbo and wind noise are louder than the clack of my 7.3L idi diesel.
I do agree with what you are doing though, the lizard skin is great stuff to keep sound out, but when I had the custom carpet made it soaked up the sound that was inside already.
Hope that makes sense.
I too am interested to see how coating motor parts will work.