I went out for some 'spirited' driving in my 2.7 earlier today, when I came back, I noticed that there was an unusual whirring noise when the car was in neutral and the clutch was let out.

I've done some searching and some people say this is normal, some say it might mean I need some clutch work. It is really faint, you can hear the difference but its not incredibly loud. It sounds almost like a fan is running with the clutch is let out, but it definitely stops when I push in the clutch.

Any advice? Is this normal or should I get it checked out ASAP?