EG Swaps - noob question

in the cx i just bought it has a d15b7 but the intake is really small like a vx manifold. now in my buddies dx he has a d15b7 but with a normal size manifold. the hp rating on the cx is like 70 hp but any other d15 its near 100hp. so is it just the manifolds that are different or is the head diff. also. i know the ecu's are diff. anything else?

up

if its the d15b7, then theres not much difference, but im also pretty sure that the 70hp motor is the d15b8, which is an 8-valve motor. so if youve got the d15b7, then swap on an intake manifold from a y8 or a z6, and you should be right up there with the DX motor.