You may remeber I found some conflicting info about the Celica Alltrac/GT-Four clutch spline sizes according to a few sites quoting Aisin (OEM) numbers and other aftermarket manufacturers.
Well I eventually got hold of the Aisin cataloge and found all of the splines are the same size (28.8), but not the size all the aftermarkets use(29.8), but the smaller of the two I had previously determined were possible. What, from cursory investigation, appears to have happened is that aftermarket makers have assumed that the 3S-GTE based cars have the same spline sizes as the 3S-GE based cars and just a larger friction plate. In actual fact the GTE has a higher clamp load pressure plate too, and higher again in later years - so its a whole mish-mash of possible mistakes. It would, IMO, explain many friction disc failures and noises ive seen on aftermarket plates and why Toyota clutches hold some mythical position as "being stock but capable of holding an aweful lot" - its may be because the aftermarkets are made wrong and so even a "stage 2" fails on a stock car due to radial play and bad loading of the friction disc. Maybe if they had the correct spline diams they'd centralise better, and carry the load more evenly - therefore not shattering, breaking apart at the springs or wearing oddly.
I'm currently chatting to a couple of aftermarket manufacturers who are taking the question seriously and looking into it.
J