Well ive had this one for a long time actually and am finally asking for thougths on it:
When i am using revs at or above 3500 rpm, i can here a fairly loud "metallic whistle" that seems to be coming from aorund the middle of my car and is much more noticable when the windows are down. I have a very strong feeling that it is coming from my transmission, due to its distinct and consistent initiation at 3500rpm and the fact that its louder outside my car than inside. Or maybe from the flywheel or elsewhere in the drivetrain since it is at 3500 rpm regardless of what gear i am in and i feel no change in the shifter feel when the noise occurs. For reference the sound is somewhat like that of a busses brakes when they make that high pitched screech/whistle sound.

any takers?

Exhaust heat shield rattle perhaps?

i dont think it would be that because it is a very high pitched sound, but my heat shield is slightly loose. ill check it but i dont think thats what it is. just another saga for me

Probably a rock lodged inbetween the heat shield and the exhaust. Take all of it off, even the shields around the cats to see if anything is there (and put them back on if you want, or dont want... Make sure to clean them decently before reinstalling them)

My tranny whines... Always has... It almost sounds like a distant siren sometimes. It’s RPM dependant and louder with the windows open. I don’t think it’s anything to worry about. I kinda like it, reminds me of a dog box.

My guess is exhaust or vacuum leak. But if it were a vacuum leak wouldn't it throw a CEL?