Clutch differences b/t 91-94 and 95-98

[cstang1968]

So I'm looking at a Fidanza flywheel and it lists the same flywheel for all 240sx model years. Then i go to the act clutch website and they list a different clutch for the 91-94 model years(NX4-HDSS) and the 95-98 model years(NX1-HDSS). If the flywheel bolts up to any year and the clutch bolts up to the flywheel, what could or would be different in the clutchs? They have the same size disk...225mm. What gives?

[cstang1968]

Well i found out that the ONLY difference between all the years is the throw out bearing. The pressure plate and disk are the exact same.