Horizon has always been top notch in CS. But back to your problem. It sure sounds like maybe you plugged the pack in backwards. That would account for the instant poof and magic smoke leakage. Word of warning, if you are using a lipo, you may want to segregate it for a while. If in fact you did plug it in backwards, you caused a dead short. For that matter even if the esc or motor was at fault, you still shorted the pack. Lipos don't like being mistreated. Keep an eye on it, as it may not show a problem until you go to use it next time.