Turbocharger for AVG Engine: Alternative Options

Hello.

According to my mechanic's assessment, the turbocharger (VW part number: 028145702S) in my Alhambra is faulty. I am now looking for an alternative. As I have already discovered, it is a Garrett GT 1749V. Do I need to stick to the specific VW part number, or can I also use a different number? I found similar turbochargers with the same numerical combination, but with a different letter.

Thank you very much.

Fimu.