They work by reducing the voltage output of the O2 sensors, which are somewhat like a battery in that when up to temperature they produce DC voltage in proportion to the difference in the amount of free oxygen either side of the element. They get their reference O2 through the wires.
The ECM reads the voltage and compares it to the value it's programmed to cause the sensors to produce. When the IEDs are in place, the ECM sees this merely as "not enough" and adds fuel to get it to the programmed level. But since the IEDs are dividing-down the sensor output, the sensors will then be creating higher voltage. There is a dependably-functional upper limit to what they output. Furthermore, the ECM doesn't just try for a fixed voltage from the sensors. It warbles the fuel high and low, shooting for the average voltage output to be correct. When the sensors are operating in their preferred environment, a small amount of fuel added or removed (in each "warble") produces a moderate change in output voltage. When the sensors are operating in their upper range, where the voltage output is leveling off, it takes a much greater amount of added fuel to result in a barely perceptible increase in voltage. On top of that, with a voltage divider on the output of the sensor, the voltage swings the sensor produces will actually appear to be smaller than they are.
So long as the rest of the ECM programming is correct in terms of how much fuel to send at various throttle positions (or intake "manifold" pressure) vs. engine speed, using these IEDs should work well, if they don't cause the O2 sensors to actually be producing voltage that's too far above their preferred range. In any event I say the "X"IEDs do this.
My direct answer to your question is dependent on your answer to my questions:
1. Is your ECM "correctly" calibrated for your engine configuration (intake, exhaust, etc.)? If so, and your ECM being "right" is the result of "everything's stock" or "everything's H-D stage one" (in all respects), then yes, (regular) IEDs will work well for you. If your ECM is "correct" because you've otherwise programmed it (with a proper, custom calibration) then you do not need any IEDs since whatever system you'd used to do the programming is capable of altering the target sensor outputs.
2. Is your ECM incorrectly calibrated for your engine configuration (maybe "stage one download" but not H-D components used to make it "stage one"; maybe aftermarket breathing parts with no ECM "download"; etc.)? If so, any version IED will do what it does just fine, but it will not make your bike run correctly. You may be able to run your bike that way for many thousands of miles. I'm not saying it'll "fer sure" blow up or anything. But it will never run as well as it could, and you'd be much happier with it if it were tuned correctly even if you think you're happy with it all cobbled up.