thanks!
Those are actually not that good, 4 times a 120mm fan would get me like 400m³/h, with a cheap Arctic Cooling F12. The reason I used those fans were I got them off ebay pretty cheap (like 1-2 each).
I plan on using nine of these:

Fan size: 92mm 55CFM, 32dBa, 3000rpm. Those should push some serious air I hope.
Anymore thoughts? Could anyone explain me why I need the exit (the left side) and not just leave it open after flowing throug hmy to be cooled units?
http://img.gawkerassets.com/img/18adxj7fzzmaxjpg/k-bigpic.jpg