This thread reminds me the day an Opel Corsa that my dad used to have when I was a teen had an ignition coil failure, and the catalyst overheated. I could feel the excessive heat irradiating through the floor.
Anyway, I'm totally favorable to adding some insulation to the floorpan of your car. I usually see some folks using those aluminium-faced reflective foils under the floorpan, even though some actually do it in order to patch rusty spots (or the holes drilled to bolt CNG tank subframes when they're not desired anymore)
