Where to insulate?

[Donunder]

Not another insulation idea but an additional approach to keeping the footwells cool -well, less warm- is to run pipes from the brake duct openings. These are for the most part just screened with some perforated alloy sheeting for the sake of appearance or left alone altogether. Why not put them to use?
I have PVC pipes running from just behind those openings up through the inner guard on each side and then mounting onto the top of the footboxes directing fresh air down to both footwells. It's a straightforward installation, no switches flaps valves etc etc and the difference is noticeable. No rain gets in. I guess if the weather turns really cold you could always just pop some sort of bung into the mouth of the pipes but that sort of weather is foreign to me. Use in connection with relevant insulation of course.