should I go into an analysis of the potatoe bake here or....
hmmm...
oh okay.... why not.

Baked Potatoe....
Couple of Q's......
Aluminium Foil.....great for radiant heat - also good for picking up any passing hot air...but if its cold air....das gutte yah....!
So next Q - I'm guessing the foil may be in direct contact with the Lifter valley. Is it contact at points or surfaces?
I've never had it out - but is it possible to get a couple of mm clearance (air gap) here?

Can the mounts be spaced up to facilitate this? Of course that would require some re-engineering of a few things. But a couple of mm - good - a few? - that takes care of the conductive component of heat....
then one could think about some possibly smarter materials - something like the jet ceramic coat (or other) for the radiant component and then....
somehow pick up a cold air intake, maybe from under the car somehow and drive it in the gap - maybe even a smallish 12V fan and remove the convective component...maybe a cryo blast (careful of the thermal shock)...;>)

Aside - I think the 3mm phenolic spacers may have a role to play here.....

Ice box.....
1kg of ice melting over a minute is equivalent to 5kW.....hmm...not bad. If it lasts longer - then lower that number...2mins...2.5kW...3mins 1.7kW...........maybe loose a hp or 2 for the eski in the back...;>) remember - we're chasing 10-20kW of cooling over stock.
Overflow might be an issue at some tracks (I think someone pointed out)