A8 FL 3.7Q, 4.2Q and S8 rear brake sizes

[A8D2driver]

Can anyone clarify the standard fit vented disc diameter and disc thickness when new sizes for the above D2 A8s (FL 99-02)

The factors seem to have both 280mm diam, 22mm max thickness discs and a 269mm diam 20mm maximum thickness disc listed for these models. As a result there are two Lucas/Girling rear calipers listed for these models, both with a 43 mm diam piston, but many suppliers only quoting a 20mm max disc thickness. Did all post FL A8s of these engine capacities and 4WD move to 280 mm diam and 22mm thickness, or are some running on the smaller thinner discs.

My research suggests the change came at chassis numbers above 4D-x-004999.

Thanks