My experience with the Swamps High Frequency High Voltage IDM is that it just seems to make the engine run better. Nothing specific, but if you have everything else optimized it is a nice upgrade. I kept my proven stock one under the back seat. Now I have an upgrade and a spare!
The Swamps unit is not cheap, but if you read up on everything they have researched on the IDM and the fact they have discovered the performance drops off over time, you are either a believer or not. They do quote some dyno results, not big HP but essentially free hp not in price but in that you don't have to add or give up anything just optimize what you have. 460/1000 on the engine dyno with 160/30's tells me it is an efficient engine. We will see when it is on the road.
Experience does tell me that if your injectors are not in great shape the HV HF IDM will make them worse.....