I run a $36 Hobbycity KD 9XL motor in a Revo but as I am geared for 30mph and have mechanical brakes not motor brakes and retain the two speed transmission, I'm not stressing it, but it still gets to 130-140f. They can be run, but it's best to consider them disposable.
Kershaw stuff is best described as functional. It works, but with no bells and whistles or extraordinary machining. I'll probably get his Baja conversion since Mike's seems to be delayed or canceled.