Just doing a little reading on the self levelling optional extra available on A6s and just realised that the air compressor unit, for the rear air struts, is in a completely different location to the Allroads. Surely the units do the same job?
I know the Allroad controls the front as well as the rears and is able to monitor each strut independently. Does anyone know if the compressors are different or is it just the compressor control units that differ?

Was the self levelling suspension a rare option?