And what kind of terrain are you on?

As for the '5000 watt' thing it depends on how you measure the wattage.
'Burst' and 'Continuos' watt ratings are typically averages taken over a time period, ie. 30 seconds for continuos and 5 seconds for burst. Instantaneous wattage can be much higher as the motor's power draw is generally far from linear.

In the scheme of things, all these ratings are useful, the 'burst' and 'continuos' wattage can help to choose a motor while the 'peak' wattage ensures that a given motor does not strain an ESC to the point where it blows.