This is my first modification for the game, this simple mod swaps all of the Emergency sirens with the Ambulance, sirens sound just like the in GTA SA / Sleeping Dogs.

Requirements:
- OpenIV

I'm unsure if this will work on FiveM, but it's primarily for Singleplayer. And, before modding. I strongly advise to backup your "mods" file before installing this if you do not like the edit.

Siren Swaps
- LSPD Cruiser
- LSPD Interceptor
- LSPD Buffalo
- Police Riot
- Police Motorbike
- LSSD Cruiser
- Sheriff SUV
- FIB Buffalo
- FIB Granger
- Firetruck
- RCV

Install instructions:
Step 1 - You will need OpenIV, otherwise this will not work
Step 2 - Drag "(INSTALL) Ambulance Sirens Swap" in OpenIV
Step 2.5 - If you get like a cirlce with a line when dragging a OIV, just click somewhere around in OpenIV and retry step 2
Step 3 - Install to "Mods" (Preferably to Mods)
Step 4 - Launch the game and enjoy the new siren sets!

Changelog (v1.1)
OIV Package Installer method.

Credits
Sirens: Rockstar Games, Rockstar North
Pyri: Edits
Stryfaar: Package installer help
OpenIV Team