This mod, sounds like the car I watched on YouTube. At first try, the sound had a lot of distortion at high engine revs and audio levels so I had to use a lot of equalizer adjustments to clean it up and also to get it sounding as close to realistic cockpit sounds as possible.
I then noticed that the sounds like the transmission whine was missing and and that the wind noise at high speed was drowning out the engine sound a lot more than expected. I wasn't able to turn down the wind noise via the AC sound controls and also was not able to turn up the transmission whine unlike the original sound file that AC came with. This made me realize how much work needs to be done to get decent sounds in racing games and how much it can get neglected in quality. I wish I knew how to do sound modification for AC because using this sound mod has made me want more. It is so close to the authentic sounds of the car it is for and a lot better than what the game came with originally.
Overall, this sound mod is very good for the immersion value once adjusted for my Z906 speakers and apart from some minor things that a fussy bastard like me can pick, I think it is a good effort. It just needs a little bit more refinement with possibly a less distorted gain/output file and separated sound tracks that allow the AC sound controls to modify the wind and transmission sound levels.