Garrett VTG-L turbocharger

Hello.

Does anyone have information about replacement parts and installation for Garrett VTG turbochargers?
In the Volkswagen parts catalog, for a Passat manufactured in 1999 with engine code AFN...
No catalytic converter between the turbocharger and exhaust manifold!
'This seems strange to me, especially considering that the VTG is supposed to be...'
A larger backflow can occur if the valve is closed or stuck!
Has anyone ever removed the housing on the turbine side? Is there an O-ring inside? Where can I find one?
can get? The parts changers at VW only have the...
Membrane dosage unit listed as a separate item in the catalog - but they want to sell it to us anyway.
Sell three expensive expansion bolts that are impossible to find anywhere in the entire installation!

Sure, here's the translation:

'Thank you in advance.'

Jürgen.

Hello Jürgen,
In the RLF (presumably referring to a specific product or system) for the old 1Z models, there are no seals provided at this location (and I haven't found any information about things like liquid sealants either).
It seems it's only describing the plan area!