It depends...By themselves, you may not see any significant improvement, certainly less than 10% gains. Where an aftermarket chipset or ECM upgrade makes sense is when you've already performed other 'mechanical', tuner improvements to your drivetrain...things like high lift cams, headers, CAI, high-flow cats, catbacks, FI (supercharging/turbocharging), NOS, etc. An aftermarket module will enable you to custom tune your engine to experience maximum gains from the various upgrades, including recalibrating VTEC engagement/disengagement points. You might visit a site like AEM, which offers a very good off-board module...these things, the good ones, can go for over a grand. They also may require a professional to make the calibrations for you. Typically, they'll have access to a dyno machine that will provide you both 'before'&'after' wheel horsepower, and engine torque graphs. Have fun!