Welcome to the forums NOTURS
Im pretty sure they are 230mm.
If you are choosing between them it depends what you want it for, the Heavy Ceramic clutch kit has a higher clamp pressure which is useful if you are putting through more power but it would probably be a bit harder to drive, a bit more bitey, I think that how it works. If your just using it as daily and not adding huge power, you might as well get the other one. Im not too familiar with clutches so someone else will have to confirm (or probably deny) what im saying...
Edit: Just like kwi_fozze says, its probably better to get a genuine clutch from subaru.