I'm not sure exactlt what happened with the whole dealership thing - but as far as I understand, the only authorsied dealers are 100% owned by Mercedes now.
From what I can see it's made a big difference to customer care. On Top Gear again last week they were saying how the Mercedes ML came at the bottom of a survey of ALL cars - not because of build quality but because of the service they recieved from dealers.

__________________
Oliver