This sound mod by Audioloids and is worth downloading and installing. It has the most realistic sound files for the car.
I review using a Logitech Z960 with a Gigabyte mobo that has a DAC chip.
Positives:
Realistic sounds for cockpit. Brake squeeling, gearbox compressor sound ( the buzzy thing), misc. car internal details are all in this sound mod. High immersion value. If you are lucky with your equipment you will get the most realistic sound reproduction from the real car.
Negatives:
The audio levels are a little bit off! When using the 5.1 channel mode from the Z960 unit ( 5.1 mode / non spdif option / room correction on) the motor's sound is a little too muted and I am unable to EQ adjust it enough to bring it up to a decent level. The other end is, when I manage to EQ the motor sound up, the rest of the other sounds ( the buzzy compressor transmission thing, brakes, kerbs, tire chirp) are too muted. If I switch off the 5.1 option and use the software's surround mode, then the resulting audio results in a very loud motor sound level but the car's other sounds details are muted. So its always a compromise between very loud motor or very loud car details.
Its like an audio troll by sound design against someone who has trained ears. This is why 3 out of 5. The file contains the car's details, but the levels needs a good tweak or a workaround to allow the user to tweak the levels a bit better. Maybe separating the motor audio to AC's engine slider alone and the other details into the game's transmission slider. If this is possible, it would beat the original and give Kuno's sound engineer a bit of a threat.
But not to be an ungrateful sob. Thanks for the effort. : )