The Audi rings on the back of my brand new A4 have a bunch of vertical lines on the top of them like they are made of plastic and cracking. Is this really plastic, or is it metal? The lines are all across the top of all four rings. Has anyone else seen this problem? Will they replace it under warantee? Should I trust them to replace it and not mess it up, or just live with the blemished symbol?<p>