Turn 10 reportedly worked with the tire manufacturer Pirelli to study properties like weight transfer, and rented out every track that appears in the game so they could study it. Spending days at each track, the developers took "terabytes" of video and photos and traced each section of the road with a GPS system.
The developer is apparently planning to capture its own audio to capture the sounds of each vehicle. The report also states that Kinect users will be able to shift perspective by leaning, similar to head-tracking technology.
Forza 4 is due for release later this year. We haven't had a public hands-on, but it seems like Turn 10 is aiming to take the simulation racing crown from its long-term rival Gran Turismo 5.