Re: foam
ah, but it's <span style="font-style: italic"><span style="font-weight: bold">special</span></span> foam.
Seriously though, it is definitely a different foam and IIRC it is called hard-cell or something like that.
I'm sure there are other foamologists here who'll clear this up, right quick. Also, there was once a member here who sold just that, for just that reason too. What his name is/was, and if he's still a member, I can't remember.