the motor kV and the 17.5 are two different types of brushless motors. If the description says it's a 17.5 turn motor, then that means it is a sensored motor and requires a sensored speedo (sometimes they also list the kV rating too) but, if the kV rating is the only indication of the power of the motor then it is a sensorless motor. In off-road, sensorless motors are more common.

"Blue Spec" tires.. sounds like Jaco Blue Rubbers... I'm guessing.

The Photon is a kit and is not RTR...