drywall opening

I am building a SFX-100 racing simulator. There will be a lot of wires, computer equipment, etc. I am locating most of the equipment in a closet. To make it neat, I required a pass through. I used the method that is common to add a drywall gangbox for the face plates. I made a nice looking cover plate, and there is the sleeve than goes between the two. This will allow about a 4" square opening where I can easily pass the wires through.