I have a JWT ECU in my 91' 240SX. Definitely pulls harder to redline, especially noticeable in a gear you can stay in longer (like 3rd and 4th). Passes Calif Smog testing no problems, even the new dyno load test. In fact the last smog was at a test only station and the CO, HC's and NOx were all below the max and even lower than the statewide average for cars that pass. Dave