Correct you need a programmable ECU something that supports retime programming is very nice, for you to be able to tune your Honda above and beyond what Honda set as factory.

You could theoretically change / adjust cam gears on a dyno also but that’s kinda stupid changing cam gear angles and not adjusting the fuel to go with the settings.

Cost depends on which car you have, which stock ECU / wiring set you have ie OBD1 or OBD2 normally obd2 wiring (post 97 honda’s ) are more expensive.

Basic piggy back ECU’s such as AFC’s e-Manage link all the very low end devices which don’t normally handle things like vtec / ignition or cold starts correctly are between 600 and 1500 These devices sux because over time your stock eca makes corrections and auto adjusts the settings back to stock… which is why you will forever be dyno tuning your car.. good for workshops because you have to keep paying them retuning fee’s !! eheh

Full tuneable ECU’s that don’t intercept singles and are a much better option Motec, Hondata, Autronic etc they normaly allow total control of your car in every possible way, allowing more tuning to be done creating a more higher tuned engine resulting in normally increase power and more driveability. They cost between $750 - $4000 depending on units.

Regards James