RC Market I don't know what you had done to the one you ran but I've had one since the euro's and it has been flawless in its performance and I have never had a temp issue at all. I don't run a heat sink on the top of the ESC and I only run the optional heat sink on the side of the ESC.
I had 4 sensors fail at the euro's but this was due to the heat and poor quality of the cheaply manufactured sensored. The sensors have subsequently been re solders (on the back on the sensor plug) and they are all working fine. As MattW it's the same for all of the GM/ORION/SPEED PASSION motors not just localised to the GM motors.