I did cut off the fan grid behind, to improve a bit airflow... And did that using no dremel tool at the time, as the computer was already built and I didn't want to take everything off / clear steel dust around. That case is like 8 years old, still doing a great job since my first build inside (at that time it was an athlon 64 3000+ on S939 ). There's a fan picking air in right in the first 5.25" slots, and that one on the back side. There are some other cuts, not seen in the photo, one on the front bay, near the hard drives, and another one on the side panel, to fit a 12 cm fan blowing directly into the video card, taking off some of the heat the 460 blasts out. This other two cuts were made with a dremel tool and a jigsaw, the drive's one before rebuilding the machine with an athlon II x4.