Do you guys know of durable the clutch of the Fabia is?

Just askinng really out of curiosity...no I haven't burnt mine out..

Depends..

the TDI clutch is... well, weak when you hit the 310lbft mark

When the car reaches these kind of figures for torque, what should one be looking to replace his/her clutch with, and how much will it cost... that was a very PC question!

It depends - there are uprated clutch plates available which may be better and probably take a little more torque, or you can replace the whole thing which can take 400ish

Cost is pretty high, have a look in Ross Clarke's gallery I think it's got summit in there on the Sachs clutch