back on the motor/esc you have now....
do you own a temp gun?
there may be some gearing left in the motor, especially if you are just doing speed runs.
Ive run brushless motors as high as 190 degrees without damaging them. If your motor is only hitting 150 or so then you could gear up.
But dont try it unless you have a reliable way to measure the temps, IE, a temp gun.