An X-hook is a mechanical device to prevent the wastegate from opening on the HY turbo. The boost fooler sits in line with the Map sensor and makes the ECM think that the boost is lower than it is. MAP is one of the parameters that the ECM monitors to determine fueling. It is not unreasonable to assume that there is some margin in the fueling algorithms. Since it does not see the 20 psi max it normally allows I think it is reasonable to assume that it will indeed fuel some past what it normally does. There will be a point at which it will not allow any more, hence the need for a box to produce better results. I do not believe that you will get more boost without some more fuel. Maybe I am all wet in this thinking, but the truck is stronger. I drive several 7% grades to work and it is holding speed on the grades far better. One of the TDR issues stated that all else being equal, 1 psi of boost equates to 10 hp. If I am wrong so be it, but it is working better some how.