ESC´s: SXX TC vs. SXX Competition

[muratti]

I read on the LRP homepage that for 4WD Offroad you should go for a SXX TC esc (which i did) and for 2WD you should take the SXX Competition. The SXX Competition hasn´t got an aluminium air cooling unit as the TC has so i am wondering why it should be better for 2WD Offroad as the TC??? Is it only because of the height? The SXX Competiton has no cooling at all and i am wondering if it doens´t get too hot...Please somebody help me