I have 93 z and I have OBD1 right, anyway I see that lot of people like OBD1, what can you do with obd1 that you can't do with obd2.

 

OBD I is a simplier to manipulate setup. OBD II monitors far more information and checks for misfires and cat convertor efficiency. OBD II also has the ablility to detect sensors that are on the way out, whereas ODB I can only sensor failures or gross miscalculations. With LT1 edit, I don't think there would be any reason to go one way or another, since you can modify virtually any parameter. However, some tuners report that OBD I PCMs respond to heavily modified cars better. I've had no problems with my LT1-edit tuned OBD II PCM.