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

I have seen the exact same problem twice on a MR2 and it was caused then the gearbox alignment dowels / pins.
 
They where not installed, this causes the clutch to run off center. They poke out the back of the block and are easy to forget to put back in, have a check and make sure they are installed.

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.
 

Definitely the gearbox alignment pins mate. Looks like one of the previous owners before you lost them...

Try Lithia Toyota or if they don't have them, i'm pretty sure u can buy generic ones from repco or bursons...

@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

Not those ones above though.   Thats not the bellhousing side we are looking at.  Iirc there are only 3 or 4 dowels between engine block and bellhousing.   Make em from steel rod. Small chamfer on bellhousing end helps alignment .

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. 
 

Not an option to go for an ACT unfortunately. At least not yet.
I've never had issues with the clutch slipping, just this.
There are no 3SGTEs, or even E153s in the wreckers here in Adelaide.
 
So if those aren't the pins I need.... what exactly am I looking for?
They don't even seem to be listed in the diagram (despite the bell housing bolts being listed there too) 

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. 

Excellent.
That would be these then?