FWIW, I don't have any dyno data but I can tell you by seat of the pants that the 2-1 ECU (#187B) made a big difference with the stock exhaust before the LV system was installed on my bike. I rode over 2K miles with this setup. The LV system improvement was minimal except on the very top, where you see the least use on the street. Don't get me wrong I like the system, it fits and sounds great and saved some weight, but you will get most of the improvement from the ECU itself.