But the reseller website says the Exedy NM053SR is for “hot street action”. 
This is why it’s so tricky to buy a modded car - you’re never sure whether the person who modified it knew what they were doing. Someone probably thought they were beefing the car up by going with that clutch.
I’d put money on it.
Adam was saying he thinks the shaft might have been damaged when the tranny was put back in after this clutch went in, but when I heard bolts were missing on the bell housing, I’m guessing that had a major part in this event, along with the solid hub clutch - ugh.