Looking for equivalents or cheap source of these 016J 5Y transmission parts

[Duke48]

My gearbox is in parts right now. I need these parts for it:

Bearings:
016 311 220E
016 311 375B
016 311 445
016 311 427
016 409 123
113 517 185C
Reverse gear spring: 016 311 859C
2nd gear synchro: 016 311 295

all can be found on page 122 here: https://www.porsche.com/all/media/pd...88_KATALOG.pdf

I know that this gearbox is similar to Audi 100 gearbox, maybe some of them are available from different manufacturers? I need help here very much.