It's a new EU directive that came into force at the end of 2014. It doesn't affect A4's before MY2016. (but your fuel consumption will still be a little worse than on 245's)Mine is a non-BE and it came with 255/35/19 upgrade from the factory, the documents state the same co2 as any other non-BE with 18's. Maybe it is because it's only an option and all BEs come with 19s?