Another way to do cutouts is to slide the bumper on a flat surface towards its destination noting where the exhaust tips want to come out. Eyeball a circle from strait on and mark out. You can cut twice, you know, so keep it small until you figure out the true circle. You'll want to cut about a 1/2 over in the end for movement, not so much heat.
AFA heat, line the interior of that puppy with some heat shield material. I never did, it got hot but as you know, it did not destroy the paint. Another driver did that for me.
