I was making in the upper 300s hp and my stocker felt like it was holding pretty good. Now that I pulled it tho, it looks like it wasnt going to be much longer.
A stock clutch may last for awhile.
A used stock clutch depending on how it's been used/abused may not last long. I had a King Cobra installed with my V2 and it lasted for 3500 miles. I have a SPEC now.
You could make a stocker last though if you don't beat on it to much.