I have a CM Storm Sniper CPU Case. It has 140mm intake on front, 140mm exhaust on the top, and 80mm exhaust in the back. I want to put it into a case holding area of my desk, but It's kind of a tight fit. How much breathing room is enough for proper airflow? The front would be completely exposed but the top and sides would only have a few inches of space between the wood and the case.