I will search the records for the material numbers and post them later.
Price??? I cannot remember except to say you are correct. The cost does hurt
but I did it anyway.  There is no real way to cheap out on this process
except for selective application and careful use. These materials are used
in sound control applications which is a special market with limited
competition and a high barrier to developing the science, product
development, marketing and limited market thus high prices. Sounds like the
parmaceutical sector!!!

EAR is the product used.

Comment: Use extreme care to assure the product is affixed soundly to the
firewall and chassis. Also make every effort to cover all the areas you
intend to cover.  Noise leaks through holes, cracks etc.  Seal the material
edges with aluminum tape for sound and air barrier.

You must buy the material in sheets which are about 2x4 feet.

Bob Smiley
N94RJ