Before you cut up your computer, find out if it's running too warm. Google "Intel XTU" and download it. This app will show your chip's temp, as well as other diagnositics. If your cpu is running in the 80c range or lower, the heat isn't really a problem.
IMO, most important cooling technique is to elevate the back of the computer, so that air can flow freely into the intake vents (even if they're small) and out the back.
There are also cooling fans that mate to the back of the PC and draw air out like a vacuum. These are the siza and shape of a pack of cigarettes and about $20 each.