You are wlecome!
You need to change the hubs, because with 256mm front discs the caliper-carriers are integrated in the hubs.
288mm front discs require Lucas or ATE FN3 calipers with a caliper-carriers separated from the hubs.
It's not a cheap upgrade, but I can tell you it's worth it!
I did it and I would not come back: even if my ABS Unit doesn't accept the right coding (so I have too much pressure on the front calipers and ABS kicks in too early), the car stops in less space and, when I press on the brake pedal, the velocity drops down amazingly!
