often also, ignition based things usually won't improve power if the existing system is working ok, but will improve the overall smoothness and burn quality of the engine
like when we went from crappy old 5mm leads, to custom 8mm leads on fook's 4age. instantly the car just idled so smoothly and built revs quicker and steadier, and it sounded alot less rough running. perhaps you could have measured the combustion quality with a gas analyser in that case?