Question about fan locations.

Alright, so i have a Arctic Cooling Freezer 7 Pro in my case right now, it's an NZXT Hades case, but i was wondering if having two exhaust fans right above the cooler could cause any form of problems regarding air flow? ie pulling air away from the cooler reducing it's efficiency. I ask as i've just bought two fans to fill the top two fan mounts on the case as having an empty slot seems to be filling the case with dust (i have no filters) and i wanted two matching fans. so could running both of them as exhaust at max 2000rpm cause any problems?

thanks guys! i wasn't planning on running the fans at full 12v though, was just mentioning that for a reference. but yeah, thanks very much for your advice. :)