Im sure any 4-2-1 header will be better than the B2 one you are running. I did a Z6 swap in my LSi hatch and ran the B2 header but then changed to a DC sports 4-2-1 and it was much better, gave a little better throttle response but you cant really notice a change but i know i got a few ponies out of it. I know what you mean about everyone wanting the Bseries motors, its the same here in sweden. I am thinking of maybe buying a LSi or a ESi from England in a year or so and if i get a LSi maybe you can help me with the OBD conections. I have never seen a write up on it except for the 4th gen civics because the 5th gens only came with OBD0 D15b2 in europe i think.