If you have a look in my RIDES thread I use a Spec Stage 3+ clutch (part number SM483F) . Im pretty sure somewhere in this forum I gave a review of it.
Here's info:
http://www.rawbrokerage.com/spec-sm483f-stage-3-clutch-dsm-4g63/
It's a single carbon semi-metallic full face and double sprung centre clutch disc. Was holding 293kw atw no problem. It doesnt like quick high rpm shifting, but then again no large single plate clutch does.
I've put maybe 5,000kms on it and its fine. It's got a very light pedal feel like stock clutches making it easy to press in and release without building your left leg muscles up like Arnie.
Best thing about it is that it IS SLIPPABLE!! which makes it perfect for streetability. You don't even know its a H/duty clutch until it grabs hard. Its also conservatively rated at 500Nm torque capacity. You can slip it when you want to or let it out further and it grabs hard. There is no unforgiving ON/OFF characteristic like many other heavy duty clutches I've encountered that use pucks. Puck clutches are made with smaller surface areas so high clamping force pressure plates make them grab hard. But higher clamping pressure plates mean you got to push the pedal down really hard which is not so healthy for a CC Lancer firewall! This Spec clutch literally feels like its a stock EVO clutch as far as pedal feel goes. It has handled 6500-7000rpm launches in my car with under 300kw atw no problem.
Now that Im making 330kw atw I haven't notice it slip yet. But my friend and brother drove my car hard one day and came back saying that he thinks the clutch was slipping during a high rpm launch. I'm sure it was just all 4 tyres melting away on the pavement which makes you feel like you're floating on a cloud lol. Actually if its not the clutch then maybe it might be the stock viscous coupling unit as I'm not sure what sort of power you can put through them before you need to consider rebuilding them with different fluid to handle launches better.
Basically if 300kw atw is all that you are after on a street car, then I would definitely tell you that the Spec Stage 3+ is worth considering (remember, its the PLUS model SM483F. NOT the normal Stage 3 model as its nowhere near as good). The SPEC 3+ is really good value for money. It's about 6 years old now but I haven't driven the car much. So they might have even improved on the friction materials and pressure plate clamping force in the meantime and made them even better.
Oh, and I use it with a Fidanza flywheel. When I last had my engine out and transmission off, the clutch and flywheel were in excellent condition and didn't even look hardly used at all. This means that it must handle heat and slippage very well as there was no hot spot discolouration on any of the surfaces.
Its got heaps of life left in it still because I've only put 5k on it, even though I have since bought a Competition Clutch twin disc clutch kit and flywheel to replace my Spec Stage 3+/ Fidanza combo when I do my next gearbox upgrade.
EDIT: Found some more info on it I posted some time ago about the friction materials. I've included a screen snapshot.
