Well you have to be using a LiPo pack as well, because the stock battery pack only delivers 9.6 volts while a 3S LiPo pack delivers 11.1 volts, so the motors are spinning faster. To keep the main motor from burning out from high amperage draw, you have to use a 9t or 8t pinion gear so it is not working as hard, but with the smaller pinion you'll be getting more torque and speed because it's more voltage, but the motor isn't drawing too many amps. This is why you also have to put on the heat sinks so the motor doesn't burn itself out from the higher voltage. So yes, using a 9t or 8t pinion will give you improved performance if you're using a LiPo pack. No use in going to a smaller pinion if you're not using a lipo pack because you won't get as much torque, and don't stay with the 10t pinion if you ARE using a LiPo pack or you'll burn out your motor.

As far as LiPo's go, as much as I'd like to get one for my Blade (I've already got a larger pack and compatibble charger that I'm going to use for another plane) I'm really worried about the lack of a voltage cutoff which could result in over-discharging the battery pack and pretty much ruining it. How do you know when it's getting too close to being overdischarged? Is it obvious enough when to quit before it reaches that dangerous 3V per cell zone?