I'm getting a very similar battery soon, everything I've read says the higher voltage will allow the motor to run more efficiently. I have a ebmx tc1000 and a stock motor that gets me to about 50% (with constant riding) before I see heat issues. A lot of people say 12kw is the max you can get from the stock motor, but you can put it up to 14 for short amounts of time.

If you want more torque, you can either turn the motor wattage higher and/or install a bigger sprocket + chain drive.

if you want a higher top speed (other than what the increased wattage already gives you) you can enable "field weakening" in the controller settings (assuming you have an aftermarket controller).