xcess, the same thing happened to me the other day! i went around a corner too fast and all of a sudden this loud whistling came about and i crapped myself. i thought it was the tyres or suspension, but then realised my window wasnt up all the way hahaha also, i get that "weeiiii" sound too. its at just the right frequency to annoy ur ears, but i always assumed it was because of my amp for my stereo. comes and goes i guess...