I also want to sound proof my expedition. Did the project was difficult? Can you provide the link where you got the material?
I had the Expedition sound proofed by a local shop. I have done it previously on multiple vehicles however I did not have the capacity to handle the project in a timely manner. They used soundshield and 3D printed the other portions. I have always used and ordered dynamat from Amazon or Jet.com previously.
not difficult at all...i've done my doors...floor...tailgate...roof is next to support my 4-18s on 30K watts...its just time consuming...i suggest to not remove all the panels at once since it sounds like you've never done this...just so u dont loose any bits...i cant for the life of me remember any of the sound deadening brands right now...but find a good audio page on FB