Jade
The air won't just be swirling round in the trunk. Cold air enters the radiators enclosure via the 'ram effect', coming in through the lower air intake (same as the RS type car in your pic) and the new upper intake. Then, having passed through the 2 radiators (one immediately behind the other) the hot air exits through the hole in the trunk where the petrol tank used to be. With a small spoiler underneath the car and to the front of this big petrol tank hole, due to the high speed of the air travelling underneath this part of the car this will be a big negative pressure area and this suction will increase the ram effect of the air flowing through the cooling enclosure. That's what I'm hoping anyway !
