Road noise missing on some cars

I drove a lot in the Camaro recently and in my opinion it's got the greatest, most authentic and dynamic road and tyre sounds I ever heard in a sim. A big C-H-A-P-E-A-U for that! :)

The wind sound in the open wheelers is dramatic and immersive as hell. And you can even hear that you're driving around on slick tyres when being in a Mini. Altogether these features combine to a great audible experience!

Nevertheless, not all of the cars have this quality. The Opala Stock Car for instance completely misses road noise, unfortunately. So my question is: Is this part of the sim complete yet?

Not only, but especially in the audio department GSC really hits all the right nerves for me and I just wish it would do so with all of the cars. :)