i read tht you could do GM ECU replacement and programming in older versions but after GM update version 5 on maxisys, no more GM programming. by mistake i updated my GM version too so i know i wont have that feature and i never saved old version too in my computer. i wonder if one of you out there still have older version and some how can email or send me the file i would really appreciate it. i belive until version 4. you could have done programming on GM.if someonne is close by toronto i am willing to travel too. thanks