“ClarettaFX adds custom sounds to The Secret World! In here you’ll find a variety of new sounds, with more being added regularly, so check back often!
All sounds can be disabled and re-enabled individually. See the installation readme in download for full instructions. ClarettaFX does not alter or overwrite default game files. It simply plays .wav files embedded in the mod .swf files when the GUI detects an event.”
More information in the original thread here.
The mod can be downloaded from Curse here.
This mod is highly recommended for those of you who care about details. BuffCalibrations is also very useful in PvE content like dungeons and scenarios.