I started my Guinea with a pair of 3S 2200s on the power pack C, but found that I would like to have more performance and longer flight times. The ESCs of power pack C are rated for 4S, as previously stated, but the motors are not. I upgraded my motors to something capable of 4S driving smaller props. The smaller props helped because the Guinea tips over easily with the narrow tricycle gear, and the 10" props would strike the ground. I'm running mine now on a Turnigy 4S 4000 and typically get 10 mins per flight.