Muffler is leaking at the seam too. To get it tight it would require a lot of welding. Not worth the effort. If I had a welder I would do it myself. In a shop it will take at least half an hour at an hourly rate of $200. $100 saved, that goes toward a new muffler. It's just a short term solution until the new muffler system arrives. The small leaks post-cat don't do any damage, since the exhaust comes out anyway.