I'd agree not worth modding the case for just one fan. Now for overclocking, is this related to the fan you were going to make room on the side panel? I'd say the CPU cooler itself plays a major role in the temperatures for overclocking the processor. In addition, if you already have good airflow (which I bet you do) then don't worry about the video card. I believe video cards can sustain hot temperatures during load without a problem.