SMS have published Ben Collins and Nic Hamilton's feedback in a 400 pages document. These posts have always been public to WMD members, but now they are available for everyone to see. I think they're really interesting, and it's certainly one of the aspects that have surprised me more about the game. I used to think about these kind of consultants as people that marketed the game, gave his image for some dollars and called it a day. Well, not anymore. Ben's feedback has been very good to read, but Nic's has been mega, as he likes to call the cars that work great. He's very, very professional, so I'd recommend you to read his feedback, it is worth it.
Link:
http://www.wmdportal.com/projectnews/project-cars-driver-feedback-compilation-available/