The Xassist.exe file you have requested: Tools and Utilities / Xassist for GTA IV - 24kb is not available. Perhaps try browsing all files for the game Grand Theft Auto IV and upload any files you want to share or are missing. This is the only information we could locate:
Automatically deletes the default control settings allowing the user to use those they define. Automatically deletes the default control settings allowing the user to use those they define. Keeps the fps at 25 hopefully making it so the final mission is passable on the first try. Allows the user to use command line functions.
To install just put the "Xassist.exe" in the GTA IV game folder and create a desktop shortcut for the program then run it.