Those that have tweaked their motors usually are doing so at the life of the motor.

Do you
-clean the motor and relube the bushings after every run?

How do you break in your motors?
-Do you use a passive means where another motor spinning the opposite direction spins the motor in question through a coupler?
-Running the motor at a very low voltage at upping the voltage over time?
-Dropping into water?

What tips do you use:
-Breaking in the bushings with a VERY thin mixture of comm drops and simichrome run for a minute then throughly clean.
-Heatsink?
-Forward only esc with a 3 wire setup for more direct power to motor?
-Repeaking your batteries just before the race?
-Adding a power capacitor to your esc line in from the battery to help with punch?
-Adding a schottky diode on the motor to a forward only esc for better breaking an less com arcing.