It looks like Thermo-Tec adhesive backed insulating liner. You can get it at Jeg's. That's what I used. It comes in a roll which you can cut to shape. It has a wax paper backing that is peeled off to expose the adhesive and you can just press it on. Seems to work ok, but it's not very thick - mostly a reflective shield vs actual insulation. I've also notice that in spots where it's very close to the headers, it will peel back if there's any seams there. Best bet would probably be this on the engine compartment side, and then some of the thicker insulating mats under the carpet on the inside.
Interesting though that when it's 98 degrees out, and 98 % hummidity, that none of this stuff seems to work. Maybe if you put a big tray of ice water in the foot box for your feet to sit in
