dont se the need of it with the case i have.
i have a backfan and a sidefan both blowing air into the case.
the backfan provides cool air directly to the cpu and upper part of the motherboard and psu.
the sidefan provides cool air to the harddrives gfxcard and lower end of the motherboard with addoncards.
the air can escape in 4 directions, out the front, through the psu, or out the holes i have on both sides at the top of the case.
i have found i get maximum cooling with the lowest noise by having the fans this way.
i have found its a big advantage to have a positive airpressure in the case as i have almost zero problem with dust now compared with when i had negative airpressure.
negative airpressure also tends to draw dust into the optical units.