Yup, modding is needed. Reason being if you only have one output, then you don't want a big hole.
I use an exacto knife and just slowly cut through. I have also used a soldering iron to make a smaller hole and then exacto out the square.
It is relatively tight. But if you feed through the case top holes, then attach to the board, then close the case, it will fit through a single opening. But I find it much easier just to make a hole above the output or input you want and then just plug directly in from the outside.