here's why; The trailing edge control of the blade grips on the factory setup are really tame, that combined with the big ninja sword blades, soft head dampening, and the baby step throttle curves make the 400 fly like a big happy butterfly (not even to mention the suck tail servo and standard mode on the g-ro), All this done to tame the bird down to let the most unexperienced pilot get in the air. But If you do what I did, you can really make this thing scream. Flip the grips and mixer, and you get leading edge control, which is way faster and way more aggressive. Go to true 325 blades, and you get another step toward violent flight, add shims to the dampening, replace the tail servo with a metal gear digital, move the servo to the tail boom, switch the g-ro to digital and do a more aggressive thottle curve, and you will then see how you go from big happy butterfly to screamin eagle! But if you flip the grips, remember to reverse your pitch in the swash mix to -60% or so, because you will also gain in pitch throw few degrees and your controls would be reversed. The swash really moves a up and down on that shaft now.