you want reliability as well, the cheap argos don't seem to last long, endevour uses 2 speed makita's on 14.4v i believe which are the same version as im going to use in Night fury 2, so on a 4s lipo with 100mm wheels should be able to do 15mph and have twice the power of the old drills, its predecessor used 12v ryobi drill which are still intact after 2 years of abuse and no maintenance but the motors did start to come loose from the gearboxes but they were easily tightened as far as the other motors i will have to leave that to others as i haven't used them