Yeah the audio is rather solid and done extremely well.
Recording with a dyno though and the end results are largely dependent on the environment.
Although I suppose they can add environmental effects to simulate echo such as when you are driving through the wide open mountainous area such as Taapaca, or tunnels on the Norway tracks. Or the more narrow and subdued effects when driving through a semi populated area such as the lap based closed circuits in India.
Outside of Forza, Project Cars, and Shift 2, Driveclub's audio recordings are fairly spot on. Here's another interesting article that covers this subject.
http://designingsound.org/2014/08/vehicle-engine-design-project-cars-forza-motorsport-5-and-rev/
I went to school for this stuff, I always wanted to get into the VG Industry as an audio engineer, but I'm not very lucky in that regard. Creating and producing realistic audio in video games is one of the things I want to do. I'd say proper vehicle sound is one of the most challenging things to do due to it's variables to achieve proper realism.
It's a shame very few developers of racing games take this aspect more seriously.