can anyone tell me when sound dampening should I apply the material to the top of the rear deck over that hard foam stuff, or should I apply it inside the trunk on the metal underside of the rear deck?

 

Metal underside doesn't help too much. What you need to do is prevent the lid from hitting the rear glass or any other items so eggcrates work for that. There are a million solutions, just have to find what works best for you

 

eggcrates was a joke whats a good product?

 

egg crates is not a joke. I used egg crates and have got rid of 95% of rattles in rear deck.

 

im sorry i misunderstood what the product was I pictured the big milk crates not the foam pad things they sell at wal mart bed stores etc. sorry bud