I dont think its an IC problem. This was a water temp light. The guys at the race shop recommended an upgraded rad and oil cooler, and I agree. An IC would help turbo performance, but thats not going to affect overheating dramatically...
Ding.
No expert here, but I suspect it is the coolant temps rising above some limit leading to limp mode.
I've never had a problem with this car or my prior FWD hatch going into overheat mode. However, with both cars, I invested in an oil cooler. I also got the Mishimoto high volume radiator for this car.
I did attend a mid-August event at The Ridge with top ambient temps in the upper 90s (deg F). Track asphalt was registering over 150 deg F around noon. I had a little plastic tire valve cover melt onto to the valve. When went to swap back to street wheels, wow, the hardware down there was HOT.
Nonetheless, I made it through my sessions without dropping into limp mode. I was not monitoring temps, so am not sure of the peak temps.
I do have hood vents, but I think the coolers made the real difference. When it is THAT hot, I'm not too concerned about optimizing charge air temp cooling, although it's always a good thing to drop intake air temps. At 98 deg F ambient, vehicle survival is my main concern.