Since ETS2 uses FMOD, understanding the "Events," "Parameters" (like engine_rpm or exhaust_load ), and "Buses" within FMOD Studio is the actual science behind the mod.
This is the official technical manual. It explains the project structure, how to use the SCS FMOD template, and how the game engine communicates with sound events. ETS2 Create sound mods
High-quality mods typically use 48kHz/24-bit samples to avoid artifacting when the game engine shifts the pitch up or down. Getting Started Since ETS2 uses FMOD
If you are looking for the most authoritative "papers" or guides, these three are essential: understanding the "Events