I just want to know who's sexy hands are holding the esc on castle's page.
(throwback thursday- way back in the day we always called out hand porn on this site

)
"1515" refers to the length and diameter of the rotor, so being the same I would imagine the motors power is quite similar.
They do note a weight limit of 11 lbs. Heavier trucks would obviously draw more current, so it appears to me they have used the weight limit to lower the current demand of the smaller esc rather than a less powerful motor.
That price is awesome! Way to go Castle!