cutting up the case

[TeLeMuNdO!]

i want to cut the fan grill on the back of my PC so that it doesn't block as much airflow as it is right now. i know this will be pretty difficult, can anybody recommend any tools or methods that they've used in the past?

 

[LV38_Eagle]

Either a dremel and follow a line, or I did this \/ with a 120mm hole saw in a drill.

 

[TeLeMuNdO!]

what kind of drill bit would you reccomend for a dremel tool? because i have a dremel, but no hole saw drill...