I had a 17' come in the shop for an oil change and the driver complained of an occasional noise. Wasn't very specific about it.. I started hitting the exhaust til I found a broken heat shield mount tab just ahead of the rear cat. I was going to unbolt the shield, weld the tab back on and bolt it back on. Every bolt broke as I unbolted it so it's not going back on today. The car has another larger heat shield right above it closer to the floor so I see no fear of the car melting down. This car only has 50000kms on it but doesn't see much pavement by the looks of the undercarriage. Here's the shield I'm talking about:
Crappy pics but you can kinda see the tab on the rh side and no tab on the lh of the pipe.