I know nothing about them, is it mechanical injection?
I wish this was a wiki so I could add the info that's missing to it, like engine designations and applicable models
https://www.tdiclub.com/TDIFAQ/TDiFAQ-2.html#aUS TDIs are 1.9s and 2.0s.
there were a few pre-turbo 1.6s in the 80s, they were IDI and about 60 horse. that's what Matt runs in the Sami if I'm recalling right. He knows the old motors well.
The 1.9 had a few generations. 1Z and ALH are what I remember and as I recall the 1Z runs in all the MkIII cars, ~94-98, VE rotary pump, wastegate turbo, and 90 horse stock. The ALH is in the early MkIVs through ~04. 90hp, VE, variable geometry turbo. prone to sticky vanes if babied all the time. both have EGR. both are computer controlled. Nozzle upgrades, turbo upgrades, computer programming are all options.
After the ALH there's two years of a "unit injector" motor, the PD. Pumpe Duße or something like that. Think Duramax.
Then common rail 2.0 motors. I know NOTHING about them. they're in MkV chassis cars that I also know nothing about.