Hi. I have a 2007 2litre quattro. I recently changed tyres all round to 18in Michelin Pilots. I never noticed any real difference straight away. But now I have a loud road noise from what seems to be the tyres, as some surfaces are less deafening. All the tyres are holding correct pressure. What could it be. It almost sounds as if I am driving with the drivers window open all the time, and probably considerably louder. btw. The tracking was done at the same time as the new tyres (approx 1k)