This is a diagram of the exhaust system, my idea for the cutout location is in red. The shape of the cat flange is shown on the left, and to transition from a circle cutout to the flange would take a few inches and then a few more to get back to the pipes. The pipes only stay together about 2 inches befroe and after they enter the cat and they split out at angles from an oval shape. I cant move the intermediate ipes back further because they run right along the driveshaft, any further back and the section where the drivers side pipe crosses over would hit the driveshaft.
