A lot of it really depends on how you handle the clutch and what type of competition you do.
I autoX and do HPDE's / Time trials. In my opinion the AutoX's are tougher on a clutch ( launches) than downshifts on the track. I do not use the transmission to brake the car, double clutch a lot.
Many people I know run stock clutches on track cars and AutoX cars without issue.
Drag racing--I do not know.
I run a SPEC Stage 2 clutch on a CA18det.
15-18 AutoX days and 8-12 track days a year. 3 years old.
PS --since you are from NH, I suggest looking into
http://www.COMSCC.com for track days and TT's --NH based club.