To be honest, the AI is not competitive at all in most of the tracks, even at 100%.
I tweaked the hints.ini file to force the AI drivers to take faster lines through the corners: the process is not so obvious as the 1.3 multiplier applied to the whole track causes the AI cars to brake too late and miss the apex in almost every corner.
I found a good compromise between corner speed, braking and early on the throttle.
It's still a very early attempt with not so amazing results, but at least qualifying now is very challenging (2:18 low with GT3 cars - 100% grip) and the race pace is faster. Unfortunately as the speed increased the AI driving smoothness may not be the best.
Have a glance at the video below to see the results.