This simple mod does exactly what it says on the tin.
It makes the cars sound like they are from the V10 era - to try and spice up races a bit (because even though the modern sounds have grown on some of us, I know many will still crave the sounds of old.)
Anyway - Here's a video of the mod in action in case you were curious what each engine sounded like -
Classic V10 Sounds 2016-09-10
Gives all four engine types one of the retro V10 engine sounds from F1 2013. Retro.