I have a slightly odd noise( not an OMG THATS TERRIBLE), but just odd(to me anyhow)
ever since i bought my 05SXT (Feb'10 54k) if i'm driving with the windows down, there is a certain position in the throttle, where i hear a sound bouncing back off passing stuff , similar to the top end whistle/chirp of an old air cooled VW exhaust.

no noise up to this position, and i can push through(past) with ease, @ which point it goes away as well..

I've only heard it from the drivers seat while going down the road, so can't be 100% sure where it's coming from, but I'd say some where forward of my butt
any bright ideas? (no i haven't checked my exhaust for small holes or anything either)

 

Does it sound like it is coming from under the hood?

 

My intake makes a whistling kind of sound under those "perfect" conditions.

 

I think there is a TSB about chamfering the holes in the camcaps because at certain times they make a strange noise. Idk if this is what you're hearing or not.

 

I know on my TB, there is a hole where the brake booster hose used to be, until they changed the design. It looks like a little tube sticking out of the front end of the throttle body. I noticed mine whistled too, until I covered the hole with some tape.