Hi, for peoples who didn't hear the sound of the car when you drivze the F12004 with slick tires, you have to NOT FIX but REPLACE the sound. (When you did the manipulation, you have next to the bottom play, "Fix vehicule". He said the sound file got a wrong name, DO NOT CLICK ON FIX IT, but look a tiny bit further down and you'll see "Replace sound with another vehicle". You just have to select the original F12004 and it's fix. (Sorry if my english is not the best, i'm french so that's why)
2) Do a steam file integrity check
3) Make sure you have the requisite DLC
4) Install the mod by following the installation instructions to the letter.
5) If issues still persist, DM me.