dividing line between prestige and premium cars

[oldnick]

as some of you might know Geneva is one of the major european car shows which is why Pirelli have just chosen to launch their latest Pzero there

as always the tyre fitments are calculated , and some half of the prestige cars are Pirelli shod and a third of the premium cars [ which reflects the Pirelli market share in those segments it seems ]

question is , does anyone know what fits in those categories ? I know the Merc S class is in prestige , what about our humble A8's ?; I presume there is an industry standard !