The 345mm
Cupra setup works quite well on the track.
Mine had a good workout at Croft last week with stock discs and pads and they coped very well without any real fade. 10 laps on the bounce with 110-120mph braking zones in a 350bhp car. Performance pads would give better braking but the discs wouldnt cope with the heat. The vents are narrow and not designed to move the air well.
They feel very sharp on the public roads but you cant compare them to a propper performance setup on the track. Had a run out in a P1 with AP 6 pots and the braking force was immence in comparison !!