I don't totally agree with The Insane Modder on equalizing air pressure. If the pressure for in is the same for out, then ya...the total case pressure is the same. But the only gain of this is??? I dunno. I can only assume that it would keep the case from whistling in extreme differentials.
I'd actually prefer more negative pressure and encourage suction from the rear. If there's any Navy engineers listening, they may get a better idea from looking at the Gas Turbine enclosures. Keeping a negative air pressure on the "case" encourages airflow around not just the important parts, but all of them. In a computer case, there's a coutless number of little gaps, holes, and slots air can come from besides the fan inlets. With negative pressure (more exhaust out back), you can actually get the flow from fan-to-fan, but also from these other "fan-less inlets". It's like a fan is there, but there actually isn't. Air WANTS to come in, so let it.
Sorry for the lack of techno-babble, but I'm really trying to dumb it down. Oh! Good experiment! Think of an attic fan (midwest people may only know what these are). You set a negative pressure by blowing air out into the attic and open all the windows. Air flows really well throughout the house with one fan. You can duplicate this by putting a box fan out one window, then open the rest. If you go to each one, you'll notice that there's air comming in from each one. The only draw back I can see is if a "window" is barely open (a slit, like where the case panel butts the case) and it squeels. Opening another window further can stop this from occuring because you're telling the air, "here...this is a better route. Don't force yourself through this little hole over there".
Thanks Chumly!! Actually i do know what you are talking about with the negative presure i actually have a engineering degree just don't get to use that end of my expertise very often so it is starting to lag.
But any way the fans should be here today and i should be able to finish it up tonight if not i will have to pack it away since it seems yet again we have a hurricane coming our way
talk to you guys on the flip side.