Easy to install/delete-
Drop the “ECHO19_FA18” folder in your /SavedGames/DCS/Mods/Tech folder. Fire up DCS. In the Module Manager, under Installed, scroll down a bit until you see F/A-18C Hornet Audio Overhaul. You may need to activate it which requires a reboot of DCS.
If you don’t like it, just delete the ECHO19_FA18 folder