By adding the weight at the grip, you actually combine the Rotational Power Generator System with the already built in Tri Voltage System making it a Voltrox Z-Force II. This should be even better – according to Yonex marketing.
You might still not get the swing speed it needs for the enormous power you can get out of a Voltrox, so you might want to get a diamond coated nail file to file the box frame to a more aerodynamic shape, just make sure to choose a thicker string to make up for the lost head weight. if you lower the tension, you also get a little more string in the racket which adds some head weight.
With these alterations, the racket doesn’t even need you anymore, just put it on court and it will play by itself.
Unless (of course) you missed that “The trend is going towards 5U rackets.”