This isn't minor though, whatever this is is substantial. It's very pronounced.

 

My exedy is noisy under low RPM decel.

 

If I have to describe this, I'd say imagine something that vibrates a lot, say a dremel tool, then when you have it on, imagine hitting the body of the dremel against something hard. You get the kind of contact vibration noise.

It makes me think it's exhaust but I have to get under it to make any more speculation.

 

My clutch kind kind of sounds like shaking a can with some nuts in it.