Hi there,
The bumper has a plastic skin with a steel section to absorb impact, it's that section you have gotten to.
You can take the metal section off of the plastic; there's about 12 clips holding it together.
If you do cut a hole, you will reduce the strength of the bumper.
Several other people have done this, look at flusted's gallery and I think Corrado VR6 - Turbo did it too!
Hope this helps :D