5cyl TURBO engine - Ignition ECU versions

Tue Oct 4 09:49:51 EDT 2005

Anybody have an idea what's the difference between different versions (letter index after MAC - number) of the same ignition ECU. I have MAC-05A ECU from my car, I saw another MAC-05C from car which is few months older than my, and now I have other MAC-05 (without index) also from KG engine but doesn't know which production year. Last night try it and car starts and idles fine.. it seems it's ok. What may be the difference between this ignition control units, and is there some advantage in one of these units? Which is superior?