I know this reply is very late but i have resently Purchased My GTA which was registered in NOV 03, has covered 23500miles and has the 305 brakes. The previous owner has never had to change the brakes but told me he did try for an upgrade. Anyway Just wanted to say that im booked on the Alfa Track day at donington so fingers crossed. I'm clinging on to the idea that there was a faulty batch of disks!!

Sev.