I think youd be better off running a complete auxillary fuel system, pump, regulator, fuel cell and all. Im not sure what kind of pressure is fed to the high pressure pump although Id have to guess that there would be enough extra volume to support a small shot. I also dont think that there is a good way to tap into the fuel system before the high pressure pump anyway. Besides, if you ran a auxillary small fuel cell youd have the option of using a high quality fuel if need be while still using pump gas in the primary tank and youd be able to change the pressure independently of the stock system. The question is, is it really worth all the complcation and expense for such a small shot. Of course, without knowing more about the stock fuel system, this is all speculation.