I know ive asked this on here before ages ago but this is driving me bonkers.....
Im in oz, i have a jap ver series 2 GSL, i took a cluch master cylinder also out of a S2, but the threads wont fit. I cant understand this as the thread change only changed after series 1. Im tryna order the right pitch, but i have no idea what one it is, they look the same.

 

IIRC, the differents between the thread pitch is one is course and one is fine. look at both master cylinders closely and see if you can see a difference. your best bet would be to 100% know which one is on your car. get that figured out and itd be easy to get a new one.