Cobblers
Enthusiast
Any case fan can be used either for intake or extract, depending on how they're installed. If you choose a case with 3 intake fans included and pick 1 extra fan, PCS most likely will install it as extract fan in the back or roof. You may drop an email for PCS asking how they'll do and suggesting your preference.
Or they will set it up to how they feel it is best for the case/components?