Still haven't figured it out, but I got the noise on camera.... I know the camera is facing the wrong way, but this noise is sounding like it's coming from the RR area of the car. You can hear it from about 3-6 seconds. I have an axleback on this car so I don't think it would have anything to do with the NPP valve because I think that's gone now haha. Is it an interior piece, a heat shield? I have no idea.
https://youtu.be/66XJXP8M2NQ