The disks (rotors) must be centered within the gap of the calipers. When you're moving parts around, there are two ways to accomplish this:
- Reposition the calipers with offset brackets.
- Use hats of different depth, so the disks remain in the same position they were in before you moved their mounting position.
I don't think the thickness of the hats warrant replacing the wheel studs. But the wheels and tires are a more complicated subject.
The front Campy clones I am familiar with could be spaced outward 6mm without issue so long as the front of the car isn't lowered too much. If the rear wheels are shod with 335/35ZR17 tires, then the tires already hang outside the fenders by about 5mm. Can they go any further? I don't know. Would they look good hanging outside the fenders by 11mm?
If you're purchasing new brakes (especially needed at the rear) I'd recommend contacting SACC, Scott has this all worked out. I would enjoy learning whatever you learn on the subject!
-G