I didn't want to make a new thread for this interview, but it happens to be called Under the Hood as well:
http://www.eurogamer.net/articles/2011-09-23-under-the-hood-of-forza-4-interview?page=2
I will just post the questions asked in the interview to decide if you want to read it:
Eurogamer: You can't get all of Forza 4's Achievements without having Kinect. Some of our readers who like to get all the Achievements in a game reacted strongly to that. Why did you think Kinect specific Achievements were the right thing to do?
Eurogamer: The EA Porsche issue struck a chord with our readers. Reading your blog post that brought this issue to light, I detected a genuine sense of disappointment that EA has blocked Porche from being in Forza 4. Is there hope the issue can be reconciled?
Eurogamer: The Kinect features are interesting. Were there any features you explored that didn't make it into the game?
Eurogamer: What are the issues associated with using Kinect to steer an imaginary steering wheel?
Eurogamer: What can gamers expect in terms of post-launch support?
Eurogamer: Is too much made of the Gran Turismo Forza rivalry?
Eurogamer: Gran Turismo has weather effects and night racing. Why doesn't Forza 4? Have you explored the possibility?
Eurogamer: Is Forza 4 the last Forza game on the Xbox 360?
Eurogamer: But more RAM would help, surely?