It is "real", because it's effectively a recording. It's not realistic to pitch-shift it, though...
PD have no way of adding the aeroacoustic "signature" (yet), and the reverb is nowhere near sophisticated enough to account for all the environmental effects captured in the recordings used to make the samples for the C9 (yet). They are committed to generating sounds (primarily for the content benefit), not playing back doctored recordings, so they will have to tackle those problems at some point. But that's fine, because they'll eventually be more expressive than recordings ever could be anyway.
And that's exactly why I'm so excited to see their work.
I've been playing with the Lexus vision GT and it's absolutely stunning. I did a little test at S.S.R 7 in the tunnel... O.O
I know there is going to be people saying, but those cars "aren't real", that the sound could be actually better..... and I know, there is work to do, but for me, they're already in the right path with little glimpses they are showing.
Another thing plenty of people tend to criticize is when somebody says that you need to have a Home Theatre to fully appreciate the sound of the game, and it's true. That being said, that doesn't mean that using a HT is going to change the samples or the sound generated by the cars, what is going to add is the 5.1/7.1 sound to the mix. And that's amazingly incredible. You just can't deny that fact. When you use one of the cars that actually have a good sound and you turn off the music and turn up the volume it's one of the most awesome feelings you can have...I was smiling like a kid with the Lexus. I even recorded it with my cellphone to show it to a friend hahaha....
BUT, again, that doesn't mean that is going to change the horrible sounds for the rest of the cars but it is definetly going to add a lot dimension to the game. When you think about it, there is people complaning about R3E O.O
Another simple thing I'd love to "add "is that I've realized that a lot of cars produce a lovely engine sound, but most of the time you can't actually hear them in real life because of the wind noise while passing. I know it sounds kind of silly but I heard that a lot lately...
Obviously, that doesn't happen with all of the cars in the game, but it's there and it happens with stock cars, which is just as in real life. NOT ALWAYS, but it happens.