Just replacing the injector o-ring seals today on my 2002 BAM engine S3. The seals I got from Audi are two different sizes a x/section dia 3.53mm (p/n 035 906 149 A) & x/section dia 2.8 mm (p/n 06A 906 149), the parts catalogue does not show which is supposed to be top and which is bottom. However, on removing the old seals they are all the same size, the larger x/section dia. I am confused as to what I should be fitting as it is possible the injector seals had been incorrectly replaced by a previous owner in the past. Does anyone know which injector o-ring seals they should be for this engine and which goes to top and which to bottom?