Note that the Fiero clutch disc has a 9 1/8" (231.775 mm) outer diameter, and that it may be slightly too large for the Montreal. The original Sachs clutch discs are marked "no longer available" as of September 2003 and were 228 mm outer diameter. Bore diameter and number of teeth are the same though.
Also, the Montreal's Sachs clutch (ZF service number 18 1861 412 102) has no cross reference in ZF's catalogue, meaning it was the only car this particular cluch plate fit.
Are there real world reports of this BBD4190 clutch disc having been fitted on a Montreal?
I realize I may have mislead people. I wanted a larger than 9" clutch disc for a specific use. There are plenty of 14 spline 9"-229mm clutch discs available. The Chevy S10 Blazer with the small engine used one, the Saab 9000 94-94 also uses one and there are many others. Type "14 spline clutch disc" into google and you will get lots of leads.