JSAudi100

I've been fighting with the exhaust system on the 100. My mechanic has replaced both the mid and rear mufflers (rear muffler OE, mid is generic). He tried two different mid mufflers, and the car still doesn't sound right. Its really loud and throaty, and occasionally you can feel a vibration around 2800 rpms. When the engine is cold, there is also a raspy metallic pinging sound coming from the exhaust when the engine is pushed above 2700 rpms. Could i be dealing with a bad catalytic converter, or is the problem most likely still the mid muffler?

crotext

Most likely is the cat. I have one acting similar but I would describe the noise as a rattle in mine. It peaks at around 4000 rpm and otherwise not heard from. Last night it started a new sound at lower rpm so now it is going to go.