Unfortunately the AI doesn't have any kind of strategy. They always go with FM 1 and pit only when absolutely necessary.
That being said, I had one odd Super GT race in Kyoto. Some cars with the best fuel economy went earlier for the pits while other cars with bad fuel efficieny managed to do 1-2 laps more before pitting.
I know the 08' Super GT cars are not equal in fuel efficieny. Most efficient is the SC430, then the GT-R and finally the NSX. In that race, some GT-Rs and SC430s went first, the next lap was 3 NSXs and me and finally the following lap the rest of the grid. Watching the replay, I can see it wasn't exactly "strategy". It was more a result of the pace of each one of them, but you know, at least adds character to the race.
I'm calling this race "Kyoto 300", because it was indeed 300 km around that track, 1:46 hours of race.
edit: I forgot about the multipliers. In this race I had 3x tire wear and 3x fuel. Those 08' Super GT cars all have the Racing Medium tires as default, so I thought x3 for a long race would be ideal for at least 2 pitstops and that's exactly what happened.