200mm clutches are only a little stronger than A-series clutch. Yes, heavy-duty L-series clutch is stronger than stock A15 clutch. But on the other hand the Nismo A12 clutch handles more torque than most L-series clutches ... the KG rating of the clutch is far more sigificant than the size increase

Better is a 215mm clutch fits. For example, SR20 clutch. See SR20 Clutch on A-series Flywheel. Same mods as needed for the 200mm unit

63-series transmission uses the 180mm clutch. 1978 B210 stock 5-speed clutch is same diameter as 4-speed clutch, but with the 63-series splines