the "15 hp chip" doesn't do squat.
here's what you should do, if you're serious about wanting power:
header, exhaust, suspension(important if you intend to get more power than intended by Toyota), better wheels/tires(to handle the speed), better brakes, build the motor, turbo(remember your fuel management!). do this IN THAT ORDER for best results.
*** please remember that better tires, brakes, and suspension are all VERY IMPORTANT if you intend to turbo the motor. to be the best runner out there, you've gotta have the strongest legs.

please also remember to RESEARCH, RESEARCH, RESEARCH!