I'm having EXACTLY this problem right now!
When the wheel is in a "relaxed" state (doesn't necessarily need to be straight) there is a high pitched whistle... like air sneaking through the ventilation system but its definitely from the steering because... apply ANY amount of pressure to the steering wheel in either direction and it goes away (until the wheel is relaxed again). I can also hear it from out under the hood, but with all the other ambient noise there, its harder to spot. But if you just stand still and listen, it sounds like a periodic cricket sound. It can be hear while driving too, but is largely masked by road noise. You notice it more by its absence whenever you change lanes.
Using my iPhone connected through the bluetooth I was able to actually capture the sound quite well. I'll see if I can post it here later. I've got an appointment at my dealer tomorrow to have it looked at... will post results.
The Super-Devil is at least 6 inches taller, has a flying motorcycle and a jar of marmalade that we believe forces you to commit adultery.