nevermind the cooling issue, that escort is
had a few more thoughts after reading all this. What if the rear quarter windows had vents in them, possibly similar to NACA style ones, but had 'scoops' covering those vents so when moving the air is forced into them rather than hopiing it flows into them. Also, with my car in particular it would make sense to get a carbon fibre intake for the roof but actually get it mounted into the sunroof area (not sure if the mk3 fiesta or mk1 in question in this thread has sunroof) and duct along the roof area into the enclosure that the rear windows are feeding. Similar to the Pat Doran fiesta but without having to chop the roof. Exiting again either in the number plate area or light cluster area (led to believe this will be at low pressure, whereas the roof must surely be higher pressure when car is travelling at 100mph+?).
I think the proper method would be as the norweigen ecos where it is brought from underneath and rear windows but for me this wouldnt be an opition, theres no way im cutting the boot floor out just to get a bit more space in the front.