Towards the end of e30 production there was a significant change to the ring gear tooth profile ............ WE HAVE BOTH TYPES! ............
Different countries got the upgrade at different times but generally around 1988-89. Also many cars have since been fitted the wrong replacement starters. (cheap aftermarket starters are generally late model version) Using the wrong starter causes a lot of very harsh noise, excessive tooth wear and eventual stripping of the ring gear teeth. There is only one way to tell the difference and that is to count the teeth.
Early version FW has 137t
Late version FW has 116t.
This change is only relevant to the starter!!... ALL other fitment and clutch details are exactly the same, so please choose the correct one