An ignition will improve engine power if it can produce a spark at a better time that will produce peak cylinder pressure at the right time or the power will suffer if the spark did not have enough voltage to jump the gap and initiate a combustion event on EVERY engine rotation.
An ignition coil cannot deliver more energy to the spark plug than is generated by the stator unless the control unit is getting additional power from another source.
The energy (power) generated by the stator can be manipulated by devices in the spark plug wires that have circuits with capacitors that reduce the spark duration but increase the peak voltage. Most of the aftermarket devices that I have used that involve special wires, different coils, plug caps that have magical devices in them have tested to be snake oil.
Dont be fooled by the demonstrations that show a whiter spark, a spark that jumps a wider gap or the increase noise or pop when the spark occurs. These devices do not change the power delivered to the plug but compress the power into a shorter spark duration. A high voltage spark of a long duration is the best way to initiate a combustion event.
Ignition coils with different turns ratios can increase the peak voltage at the expense or reducing the current and spark duration.
One way I have found to determine if a programmable ignition would benefit a particular engine is to try many different timing settings by advancing or retarding the timing by rotating the stator a degree at a time . If the OEM timing curve is not what the engine wants at all RPMs, we will see the power improve in the RPM ranges where the engine liked the new timing setting and the power will decreases in the RPM ranges where the timing in the OEM curve was optimum from the factory.
With my current engine packages for the LT500s (ports, pipes, heads, carbs and reeds) the OEM timing curve seems to be very close to what the engine wants at all RPMs. If I advance the timing more than one degree power usually suffers through out the whole usable RPM range and retarding more than 1 degrees has similar results.
If you have a good OEM CDI box and stator I do not think that you will benefit from using any of the aftermarket ignition assemblies or coils, wires etc. unless you are doing something that is vastly different than the zillions of things I have tried over the years.