ive checked this with the engines i have at home, the RB25DE has far more common parts with the RB20DET than the RB25DET, ie top feed injectors, same stud pattern on the intake (albeit with slightly bigger ports on the DE) the RB25DET intake will NOT fit the RB25DE head . . .different bolt pattern- different size/shaped ports, only the water jackets line up! (can supply photos if you wish)Brendan- does your aftermarket manifold come with provisions for bolting up the idle air controls , brake booster vacuum port etc?