[pmolina]

Maybe to allow for seat recline?

YEp, That's it. They are reclining although not fully reclining.

 

[pmolina]

A couple of quick vids put together.

STOCK INTAKE



AEM INTAKE

Unless the microphone is located near the exhaust exits, this sounds like it is the 'fake' sound generated from the engine manifold area thru a sound tube and exits the instrument panel and thus entering the cockpit.
I had a Ford Focus RS with this fake feature and I disengaged it.