Hi, the brushless would be a very good way to go. You will need motors with high torque to turn the props and get a nice speed out of it. High rpm motors will not turn the props very well and your runtime will be very short. Try going with a brushless motor that is close to the astro flight 40 marine motor or the 25. As far as couplings ditch the dumas u-joints. They will fail on a high power motor. try direct coupling or a high quality u-joint.