00 Si, stock b16a2. tonight i went to get some food, on the way back I was just fuckin around and revved to 5k and shifted. i started noticing this really, really faint whistling sound that started around 4500 rpm and continued until 5500 rpm. I couldn't hear it after vtec engaged, but i'm betting it keeps on going. it's about 28 degrees outside, and i just had my belts (serpentine and timing) changed just 3000 miles ago. what could it be?