Quote Originally Posted by fordf250 View Post
I posted some time back the drill bit size to counter sink any fan hole so the stock clips fit. I had 2 120cfm 38x120 fans on it with a third as exhaust on the case, it worked well but was way to noisy for only a 5-7C drop in temps.
Countersinking. Minimally invasive, but oh so careful in gauging the depth to drill.