Re: safc on a E36??
Cant find my thread on the SAFC II for your perusal...
If I remember correctly, the SAFC only allows you to calibrate the A/F ratio, throttle opening position and rpm but not ignition timings.
Becareful when you tune the A/F ratio, too lean will cause ping(detonation) and damage engine.
If E36 has OBDII, then all the more difficult to tune cause it has a close loop system which will adjust the A/F back to stock and this will disrupt your fuel trims which may give you power initially but eventually lose power after 30mins or next day(s).
Best is to ask the person selling you the product if it is suitable to BMW and power remains till next tuning.
I know ST Power have SAFC II for BMW.
Cheers!