They're crap ... stick to the floor if you give them a hard time.
Bad design of the pedal and the slave cylinder is too small compared to VX.
Problem is compounded by the traction control with high output cars like mine.
There are lots of threads on the topic on other forums ... I have posted a fix in here that gives a step-by-step instruction to do a mod which removes the helper spring and adds a return spring to stop the pedal from sticking. see here:
https://forums.justcommodores.com.au/threads/fix-sticking-ve-ss-clutch.118418
Holden are apparently working on a "fix" but this has beein going on for years.
There was talk of replace the clutch with an LS7 clutch (E2's and W427 have them as standard) However while the extra force of the stronger pressure plate overcomes the issue ... it doesn't actually fix the fault.
You only have to remove thecap off the master cylinder and look at the build up of black gunk around the edge to know that there is not enough fluid in the system and it's overheating.
I did my fix in Sept ... and it is still going fine ... keep in mind that if you drill a hole in the pedal arm then try and do a warranty claim when they come up with the fix, they may knock you back. I suspect the lumpy cam and 310rwkw's will be a bigger warranty issue for me than a 1/8" hole in the pedal!!!