I've been using the Nissan 550Kg pressure plate with a standard clutch disc.

I don't even remember what brand of disc anymore because I haven't purchased one in probably 15 years. When we stripped various cars/motors I always kept the clutch disc if it was within tolerance. The one in the car now has at least 25 events on it.

Granted the old motor only made 80whp and the A15 is putting putting out more than 110whp, additionally I'm only doing about 5-6 events a year and we do rolling starts. I'm also mindful of the clutch.

I'd be reluctant to use a button clutch on the street.