Use an IMG Tool to replace player.dff and player.txd in your gta3.img file. Scripts: Drop any .cs files into your CLEO folder.
Some older "Robo" mods were less about the movie character and more about adding pilotable giant robots or "Transformers" style mechanics to the game engine, often utilizing Cleo scripts to trigger transformations. ⚠️ A Note on Safety
Replace vehicle or weapon files in the models directory.