Customizing GTA4 mods

The following software (SparkIV) can be used to open GTA files (.rpf) for you to mod. I use this to change some sound effect file that can be located at 'C:\Program Files\Rockstar Games\Grand Theft Auto 4\pc\audio\Sfx'. The possibilities are endless with this. You can change the GPS voice, vehicle engine sound or just simply preview and listen to how much effort had Rockstar give to produce this popular open sandbox game.

The only problem that I had is that after playing the sound for some time it will crash. Nothing to worry about as a simply relaunching the program will do.