Is this howling I'm experiencing under full throttle a typical characteristic of the W8 motor. I'm calling it a howling sound. It's a bit high. Some may call it a whistle. I'm pretty sure it's not wind noise from the exterior of the car.
It would be a good idea to try and capture the sound via a video as VAGguy suggests.
I can say that both of my W8's make distinct noises at certain rpm's.
My latest W8, a 2004 that I purchased from member JayTheSnork makes a very distinct sound, almost a whine to it.
It leads some people to believe that it's supercharged.
I'll admit, I have no idea what generates that sound but it's exclusive to the W8 motor.
Just went and had a test, no unusual sounds here. But I wouldn't be surprised if something in the intake path plastic has developed some sort of resonance on yours at certain loads over time though. My Jetta did something similar after I'd had it for a few years.