Odds of any ECU tuning are slim to none without daughterboarding it which will cause havoc on the warranty and who knows what else. That's the only way it's worked in the past with Toyota ECU's. They are super sneaky with their coding.
Honestly, a cold air intake and full exhaust MIGHT net you a few extra HP, but the secret sauce is in the electric motor.
Some Prius guys have managed to run the car on a user selectable mode (100% electric, 100% gas, or traditional) and managed 100+mpg around town. You just need those same guys to help find a way to double the voltage output of the batteries when you crank on the skinny pedal. Double the voltage, double the electric power (or thereabouts)!!
Of course that would be for quick sprints, passes or 0-60 runs. Regardless I think there's potential. It's only a matter of time
That, or do what Team Lexus does.... own a fast car on the side to get it out of your system.