Will this be a closed case in the end, or will it be more like a open testbench? The reason why I'm asking this is, that you need exhaust-fans. For a good working setup there needs to be as much air being exhausted as is pushed into the case. Otherwise you'll get a negative airflow, resulting in turbulances with the possibility of increasing noise or in worst case increased temperatures. Because of this I usually don't use fans to push air into the case at all, but only use exhaust-fans, which draw air into the case by creating underpressure, if you get what I mean. This usually reduces the fans used (less noise) and works like a charm for me during the last years, not having any issues with temps either.