2009 R3 67k(km). Cai, bhr midpipe, mazdaspeed exhaust. Car is stock.

First start of the year, there is a scratching sound when decelerating, pretty sure it wasn't doing it last year before storage.
New engine/trans/diff oil. Could something be rubbing against the flywheel?(Then why would does it make the sound only when I let off the gas?)

(Car is on jack stand in neutral)

 

Upon further investigation, I'm 95% sure the sound isn't coming from the transmission but from the exhaust manifold/ the start of my midpipe (Black Halo Racing resonated midpipe (No cat)). Could this be engine related (e.g. engine mount) or something as stupid as manifold bolts/ pipe bolts vibrating and being amplified through the whole system?

 

I would start with checking the heat shield on the exhaust manifold it could be bent or bolts rusted out causing it to rattle from engine vibration. also would be in the area you say the noise is coming from. Easy thing to check before getting more into it.