I have a 03 305/555 motor, what injectors came stock with it? I read some folks change out to 50 HP injectors to "get better fuel mileage" How does this injector business work? I read in previous post to make more power you need more fuel so bigger injectors give more fuel? How does this increase mileage? What would the optimum injector be for this motor be, if it just had exhaust and intake and a smarty? Thanks