Just a comment on AI lap time consistency at Melbourne on a 40% race, short weekend. (on intermediate difficulty).
In practice I set a lap time in the 1:29s and finished 17th. In Qualifying I did a 1:27 for pole while Mark Webber (2nd on the grid) posted a 1:29. Then in the race the AI seemed to be lapping in the 1:26 range which is unrealistic considering they couldn't get near it in a light car in Qualifying.
Probably because of the lower difficulty.. Everything works perfect on Legend.