THANKS for your answers.
@Cram: i assume that some of the different digits are date/lot codes, but your 997/91 vs my 997/94 on the muffler is surprising. Excellent color choice btw ;-)

@Fritz: the car will be deemed road legal by Porsche of Switzerland themselves (formerly AMAG), not trying to do that myself. They will issue the emissions and reg certificates, they have a standard fee/service for that. All I am trying to assess is the likelihood of a change in the exhaust system as they said it *may* be the case. Can't be the cats though, would be more expensive that what they were talking about.

@porkernut: I could not access the PDFs myself, I just registered to techinfo and will try to get them myself but my browser errors out. If you could send them to me via email, much appreciated !