I just did the 30 lap race at Susuka in GT league and had a lot of fun. I just try to stay away from the IA and only overtake at obvious opportunities and not try to squeeze in every little gap. I even noticed that when you start lapping the AI they don't drive on the raceline anymore. most of the time I could follow my own preferred line. And if I see that one is sliding all over the place I stay behind it and wait for him to spin out. (which he WILL do ) I really wish that the real enduranse races from the older GT's (GT1 - GT4) are brought back, loved doing the 4h on the Nürburgring on a lazy sunday morning.