Try this SubSim page for the downloads:
THE NYGM Super Mod, Version 3 (and its sub-versions)
The "Release" thread:
NYGM 3 Super-mod
There is quite a bit of reading to do to wade through it all. Fifi has done an updated version of the mod that you might be interested in:
Fifi Enhancements for NYGM
Several others around here are old hands at activating NYGM. The main thing about modding SH3 is that you do NOT want the game installed in a Program Files folder, which is what it defaults to for its install. Windows has too many "technologies" that thwart any attempts to modify files in that folder with JSGME and mods...