A guy at racing with a 16018, 1650kv align 600XL, and 6s in losi 8t gets his esc pretty hot after a 5 minute race, much hotter than my quark on 5s geared for around the same speed. His has thermalled as well in a longer race. Him and another guy both burnt out the bec's in them as well. I don't know if it's to do with settings or not.