I'm not saying it should be legal, but I don't think it gives you more speed.  My fastest time (the 22.659) is within the white lines, which is where I run.  This one lap I'm talking about is within the white line right up to the rumble strip, when it clips a cobblestone.  My fastest lap does indeed cross entirely over the white line, so I would never submit it, but it's still a full tenth slower at t1 (it's a 22.783.)  I was just wondering about that one stone.  If Jake gets here, I'll post a picture.  But I do agree that the cobbles should be out, I'm trying to let people know to watch out for it, that's all.