Although different companies all ahve "stage 1" "stage 2" and so on, there is not standard of clamping force or hp capability depending on the stage. IE an exedy stage 2 may hold more than a act stage 3. Although everyone above is talking about exedy, so I guess that doesn't really matter.
Personally I have an exedy stage 1 in my car and it's pretty nice. After driving 500 mi the pedal has gotten a lot softer - i liked it really stiff.
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