Installation:

1. In OpenIV, go to pc/audio/sfx/resident.rpf/RESIDENT
2. Enter in Edit Mode, and drop the WEAPONS file

Optionals:
In Optionals, you have an edited SOUNDS.DAT15, which edits the tail sounds to be better heard in-game, you can drop this in audio/config, and replace the file. It's reccomended to use this to fully experience this mod

If you have a mod that edit this, such as The Actual Complete Edition or Revamped Combat or if you want to do it manually, i got a topic in GTAFORUMS:
https://gtaforums.com/topic/995647-ivtut-louder-tail-sounds-via-rageat/

Credits:

MesserAR: for passing me the JSRS Soundmod files in Google Drive
AlAlvarez: For being one of the testers, and giving me a 10 star rate in the older version of the mod
DayL: For giving me a 10 Star rate in the older version of the mod
Jarhead: for making Arma 3 JSRS
Solarint: For making Anomaly JSRS, and giving me the inspiration for doing it for IV.