|All that's required is a single exhaust fan in the rear, maybe two - it depends on the capacity of the fan & how paranoid you are about temperatures. Anything else is overkill.|
Do the math. How big is your tower - maybe 1.5' x 1.5' x 0.75' ? That's less than 2 cubic feet. Using 2 CF for easy math, a single 250CFM rear exahust fan, will completely refresh the air in the case 125 times per minute. Now ask yourself, do you really need more airflow than that? Read the article I posted in response # 3.