For those hardcore St170 fans out there (this post and car are pretty old) I recently purchased an ST170 solid mass flywheel conversion kit from RTS Performance. It still needs bedding in but I am pretty happy with it so far.

I thought that I would share this as the post shown up for me when I search st170 clutch on google.

This is the kit that I bought:
https://www.rtsperformance.co.uk/pro...iction-clutch/