Hello again, CabConModding!
Although the ps3 scene is now merely dead, I've been working a basic tool that some users may find interesting and cool for everyday modding!
An open source desktop application designed to easily browse through a regularly updated database of game mods, homebrew...
Here can you find all about GTA 4 Mods, have fun!
GTA IV Xbox & PC File Editing Programs
Use this to open the GTA IV .rpf and .img files, it also lets you extract and replace files within the archives. This will be needed to edit or make your own custom mods.