The CC 17/17 would have more torque than the other.
The 1521 would have a little more torque than the 1520, as its rotor is a little longer, but they are very close. Maybe the real neu is the best one for efficiency and weight.
Other than that theses three motors are beasts in 1/10 MT like E-Revo
i am pretty sure i saw on the castle site that the 1717 is 50mm dia motor. much larger and heavier than the 42mm 1520 or 44mm neu 1521. so as stated, it will have more torque. might be too big to get in a revo.....and way overkill. but hey, have fun!
Jammin SCRT10 Neu 1512 1y
Losi Ten-T SCT conversion Neu 1512 1y