Regarding mirrors
First of all, their size or the size of aperture is not tiny. Just remember Mclaren's really tiny F duct inlet and how huge impact it had on overall performance.
Also, I'm absolutely sure that they are definitely not used for driver cooling, since it has to be done at the front of the monocoque, not at its end.
They might not guide the air into sidepods exclusively for basically persumed radiator cooling, I mean, they could have separate ducting for cooling of electronics or whatever.
When it matters as some suggested that they also guide the air into top sidepod inlets, I agree on that but with a theory of mine:
I think that mirrors are designed to choke on high speeds which completely changes the airflow behind them, with possible desired effect of not guiding the air into top sidepod inlets, thus lowering the drag. If turbulence they create at high speeds/straights decreases the drag of the rear wing, while not doing so at lower speeds/corners, thus aiding the cooling, than they are ingeniously multipractic.
In case my semantics sucked so far, let me explain it like this.
1. At low and medium speeds, in corners, when the DF is highly desired, they clean the air that reaches the rear wing by reducing the turbulence, and by picking it up and also by conditioning it into top sidepod inlets, they also improve the cooling.
2. At high speeds, on straights, when DF and rear wing drag is least desired, they choke, stop conditioning the air into top sidepod inlets (lowers the inlet-caused drag) and cause even more turbulence than conventional mirrors, which results in decreased ability of rear wing to create DF and undesired drag that rear wing creates while generating DF.
Another possibility could be that they can't condition the air into top sidepod inlets until they choke, and with that reduce the amount of air that reaches rear wing, thus increasing speed by decreasing the DF/drag. That would also mean that top sidepod inlet has separate ducting that passes the air to the rear end of the car without hitting the radiators, in order to bypass the rear wing at top speeds.
Basically, I think that overall goal is higher top speed, with more DF on low and medium speeds, which is everyone's dream.
Oh yes, someone asked me about the overcoming the sidepod's pressure... Well if my theory is correct, than they are not even intended to be able to pass the air trough ducting at high/top speeds, since they should choke as explained.
