G'day Mate,
Go for the OS 160FX, great motor, will haul the Yak around with authority. & about receivers you may find that you will need at least 7 channels to set up & fly the Yak properly, & avoid "Y" leads, 2 Aileron, 2 elevator, 1 high torque on rudder & 1 for throttle, thats 6 channels, but remember there is always a retract channel that you can't use, it is not proportional.