I want to cut a hole in the bottom of my case and put my 120mm fan in it as an intake fan. And then I'll build a wooden box for my case to sit on that opens in the rear and for my fan. I'll then block off the front intake of my case all together and exhaust with my rear case fan and PSU. My objective is to quiet the thing down while still getting good air flow. I figure the box will be as long as my case and about 3" high, so the opening in the rear will be about 3" x 7". Any thoughts... good or bad?