I ran my 3100kv ROC in my Slash 4x a few times. Threw it around like a rag doll - very strong motor. I didn't have any heat issues at all. Guys use that combo to race U4, it will be fine in a somewhat light Slash.
In the end though, I swapped it out for a Castle 3800 4 pole for a little more RPM.
Like any motor, just keep an eye on temps and it will be fine.