Have you checked the rear wheel alignment? There is about 4 or 5 mm clearance between the belt and tyre sidewall on my car and no problems with noise and the belt runs central on the sprocket. The photo shows your belt running to one side and possibly touching the sprocket outer side plate. This should give more tyre clearance not less, if it is all running in alignment. I would still try and get a new (steel) sprocket under warranty for a longer term fix.
My belt seems to have the same clearance as yours and seems to run to one side (away from the tire), which should provide more clearance. This is what baffles me. I know for certain that I heard the belt rubbing the tire once when I made a hard left and it made the most awful squealing noise. Since then, I can't say that I've actually heard it occur, but it is still making the swirling noise on deceleration when the clutch is engaged, which is probably also caused by the belt based upon Michael H's comments above.
It sounds like I'll have to make the 200 mile trek to the dealership to get this diagnosed.
