You should be able to pickup an OE Bosch fuel filter at any good parts store. A store with an import focus, as opposed to a big chain, might be a better bet. The OE filter is undoubtedly a Bosch product, car manufacturers don't make filters, Mercedes included. You could buy the exact same Bosch filter at an MB or Chrysler dealer, you'll just pay more. I can't imagine why anyone anyone would think the fuel pressure regulator comes with the filter, no way.