having owned both an SI and an SR, i think I can shed some light on the subject. the only difference I have found is that the SI has 4WS (four wheel steering) and a passenger side airbad, and the SR (canadian version) does not. still the same H23 motor, my SR does not have heated seats or mirrors, either. having driven both for extended periods of time, I can tell you that the 4ws makes hardly any difference in cornering at all.