The 1998-2003 NB TDI engines are the same as the 1999.5-2003 Jetta/Golf engines.
The 2004-2006 NB/Golf TDI engines are the same as the 2004-2005 Jetta.
After 2005, the Golf and NB used the older engines and the Jetta got a new engine. The NB also got a dsg tranny one year too.