Just a heads up, but if you are running any motor topped out at max rpm for long periods of time, they will heat up. Motors seem to like partial throttle, while ESCs like full throttle. The trick it to find a gearing for a particular setup so that you only hit and stay at max rpm about 10% of the time. Also, lots of WOT starts will heat everything up since that's when you are pulling lots of current, therefore generating lots of power.
Of course, bad soldering joints does make a difference.
