Structural Foam for chassis stiffening

Most of the late models I've been into, and it's been many, in addition to the foam there is also plastic gussets in place whether it's in a sail panel or rocker adding some kind of mechanical advantage. The adhesive properties of the foam make them a bear to get loose when replacing panels. I don't see a retrofit being worthwhile other then sound deadening. The stuff will make a tin can sound solid.

So foam was meant to flow in and around these plastic gussets or were the gusseting more to contain the foam in a certain area? Do you have an pictures of what your referencing?

If the best outcome had is sound deadening, nothing wrong with that.