Les - have you seen the insulation on my car? I was paranoid about heat inside the footbox, as I extended the driver's footbox by 8". This put the back 3 exhaust pipes almost hard up against the footbox.
I have HPC coated the headers.
Most of the header length is HPC coated
There's an airgapped alloy panel inside the engine bay.
There's some alloy-bonded fibreglass matting style temp shielding stuck between the alloy panel and the footbox.
The alloy/fibreglass matting is also inside the footbox.
Then the carpet.
Then my shoes
Then my socks
Then my dainty little tootsies...
I guarantee that you can not feel the slightest bit of engine / exhaust heat inside the car. Nothing....
I was all set to install something similar to
http://home.mindspring.com/~egroce/id1.html , but it's absolutely not needed.
I went overboard, but I'm sure if you had the pipes HPC'd, then attached a gapped alloy / stainless panel, then fitted this alloy/glass bonded material against the engine bay side of your footbox, you wouldn't ever have a problem.