IbanezDan51:
I would like to use these Cupra seats though, but wouldnt be able to use harnesses with them 
The standard brakes will have to be ok for now though as I cant afford anything better! Although the next set of brembos to come in of an LCR have my name on them.
It's a project - use the cupra seats for now to get it running and rolling and on the road, then when time and funds allow, stump up for some proper seats and belts!
As for brakes, the 312 set up will more than stop you, the biggest issue is dealing with the heat generated by repeated high speed stops. A decent set of pads (DS2500s, Pagid Blues those sorts of things), some discs with a high carbon content and some RBF600 brake fluid will be more than sufficient. Although 4 pots look big and nice, you can only brake so much before you lock up your wheels.
However, one big advantage of big 4 pot calipers and two piece discs is a reduction in unsprung weight and an ability to cope with the temperatures.
Jon.

BMW E46 330d Sport Touring // 1/3rd VW Bora 1.8T Track & 'Ring