Ok, guys...my N/A gt started whistling this morning between 1/3 to full throttle. Its sounds cool, but worries me at the same time. I was trying to follow all of your posts in this thread, but got lost. My car, however, doesnt whistle at idle or cruise speeds that I can hear. Would this be a exhaust gasket leak?
Note: it was about 20 degrees (F) out this morning.