Here's another great weapon from FFX (Final Fantasy 10) the Masamune which is Auron's Celestial weapon in FFX now in GTA San Andreas

Replaces: Katana.dff ~ Katana.txd

Installation:

First remove all the files from the .zip folder

1st Way. Use any img editor (Recommended IMGTool) open up gta3.img located in Rockstar Games / GTA San Andreas / Models, Find and delete both the Katana.dff and Katana.txd now add the one's from this mod,
Done (no rebuild of archive required)

Or

2nd Way. Open gta3.img then find and replace both the Katana.dff and Katana.txd with the one's of this mod once done go to commands and rebuild archive (IMGTool)
Done

Enjoy