Ill hijack this one as ive got the same problem. Had it ever since i got it and it had the stock airbox in. Never does it while idling or revving while idle only when accelerating, noise sounds like it comes through the aircon but could also be the gearbox (Note: does it whether the air con is on or off). Its pretty damn loud and i actually like it gives a nice whine, its not like a pod filter whistle more like a charger whistle lol. Whether its bad or not well nothings died on me yet.
Im leaning more towards it being the throttle body