Think there is 2, or 3 versions of the impact reg, all depending on what generation of gun. The huma might be a better solution than the oldest generation FX reg? But I have see some post where some are changing out the AMP regulator for a huma, where the AMP actually perform better. Some has tested the AMP gives a lilte less pressure drop from a full fill, and down to the reg pressure, while the huma may have 5-6 bar difference. I happen to own both a impact X, and a wildcat mk2, with a AMP reg. From a full fill, and down to a litle higher than reg pressure (I do not shoot below reg), both stay within 2-3 bar difference. The reason I know this is because both gun has a EDMU gauge fitted on the reg side. Measuring that difference with the stock gauges would be difficult. But to be fair when comparing a AMP to a huma, the AMP will usually been "broken in", while the new huma probably need some time shooting. But the huma gives great benefit if you have a older style gun, and like to experiment with different pressure, as they are easier to adjust. And if the stock reg is not working properly, it can be a good oportunity to swap it out with an easier adjsustable huma. The huma has one other benefit, and that is they in some guns are smaller, so they give more room for air in the tube, or a bigger plenum space.