well if your using the b16 harness. theres a spot for the front o2 sensor and on the back side of the harness a plug for the 2nd o2 . you didnt say what kind of exhaust your running but im guesssing your running a stock b series manifold bolted straight pipe to your dx exhaust. your gonn ahave to either get a bung welded in, or get a cat then an ex or si midpipe and a hatch axle back. since any performance exhaust you get for a hatch is gonna be for a dx with the close coupled cat. email me if you have more questions