I installed the BMW M3 GT4 power steering cooler last week and the overheating of the fluid is gone. Doesn't take that long to install.
Previously I only had the little tube running out of the hole. It got all soft from the heated fluid.
Now the tube stayed "nice and hard" even during six fast laps on the Nordschleife. Big difference! Better for the whole system as well.
This is one of the most important "mods" for the M3 if you drive it on the track (besides proper brakes with cooling, 18" Cup tires and a different alignment).