Several of us are using Primos on air. They work very well! I'm using 9 case fans, but 5 did the job with no problem. I used all 5 as intakes; 2x front, 1x bottom and 2x top. Case has so many vents and the PH-F140SP fans easily give case great airflow. I only added the additional F140 SP fans because I got a deal I couldn't refuse.
Only "mod" is a castor base for ease of movement and better airflow to bottom intakes.
Sounds good to me, thanks.