I'm not a TDI expert by any means, but as far as I know, the Pump Deuse with the unit injectors is the least desirable TDI. You either want the older one with the traditional distributor pump or a newer one with the HPCR system. The PD is the one that can have camshaft issues. It is also not quite as economical as either the earlier or later version.
I had not figured that out as you stated it but it makes perfect sense when considering what I read about the Pumpe Deuse (I think that is the odd way it was spelled). It is reportedly the one that causes worn cam lobes.
The 2004 and earlier apparently use a mechanical fuel delivery system much like the 12 valve Cummins - mechanical pump. That system may run forever. The latest ones have the DMF!
I've had zero problems with the DMF in my C&C but given the choice I'd prefer not to buy a small car intended for the short trips and fuel economy my heavy C&C does not excel at only to have a DMF that doesn't like short trips.