the background info: my integras got a b20z block with b16a head, stock internals on the bottom and the head has springs, reatainers and just some GSR cams for now. other than that is just bolt-ons... cat back exhaust with test pipe, short ram intake, type R throttle body so the car isnt all that fast, although it runs excellent, like it came from the factory this way even. no CEL, purrs like a kitten. i just put a 4 into 1 stainless header on it and it feels like it lost power compared the oem cast iron POS manifold first im wondering is it the ecu holding the motor back?... it is just a stock p28 (i think they are for single cam vtec) and it hits the rev limiter so soon. also wondering why i would feel a loss in power after adding this header?