Clutch plate troubles...

Mr2 fanatics, aficionados, wizards, geniuses, and plebs! (I'll let you work out which one you are)
 
See figure 1 below.

 
Now that we've sorted that. What the hell has caused this TWICE with two different brands of HD clutch?
Exactly the same damage.
A bit of background....
The first time, was with a standard Gen 2 ECU, standard injectors, boost controller and a hiflowed turbo. the clutch was an Exedy HD.
What I have recently found out... is that the 'hiflowed turbo' is actually a GT3582 core with standard CT26 housings. 
 
2 years ago, I overhauled the car. I had owned it for about 2 years at that stage. (which means now 4 years in my possession)
I replaced the clutch with an Extreme HD. (KTY24006-1A)
At that stage I also replaced the slave cylinder with a DIFFERENT MODEL. I had found on MR2OC that single port Camry cylinder have the same dimensions and are much easier to bleed. So I swapped it. (bear in mind, this was AFTER I noticed the damaged clutch plate)
 
The gearbox had been getting noisy lately, It sounded like the release bearing, and I decided to replace it. In the bell housing I found a tiny piece of the spring. Figure 1 is what I found.
 
I haven't had the car on the dyno, but surely it isn't making too much power for the clutch.
Any ideas what might cause it?
Thanks,
Tim

Hmm... great.

You mean these guys?
I don't recall ever having them in the gearbox. I've removed it twice now and definitely haven't had them.
Looks like i'll be chasing down a few.
 

@3sgeturbo haha i was gonna say the same thing, but i knew you would get onto this, u forget to mention one thing tho..... ACT > EXEDY :P

I would just go the wreckers and ask for them, you can pull them off a blown motor.
 
Also if you are running an exedy is would recommend you get an ACT, my two was slipping on a Exedy HDB clutch and the car was not even tuned.
 
I spoke to extreme clutches and they told me there clutches are the same as exedy as they come out of the same factory, got an ACT from the states and it was the best thing I ever did. 
 

They usually won't be in the gearbox diagram,
 
They slide into the back of the engine block and stay there so they are usually in the engine manual, you can use pins from any FWD celica or corolla with a 3S motor, even 3SFE pins will work as Toyota make them all the same diameter and length. 

Yeap, that's the little suckers