Brake uppgrade FL

[Fredde]

Hello i am working on upgrading my brakes on my 2001 A8L and so far i am working on c6 s6 385 mm front brakes but i dont know exactly what to do for the rear but i want to get the 335 mm brakes from the vw phaeton v10 tdi it seems i could make the caliper and disc work with possibly some spacers and longer bolts or machining the caliper carrier but it seems most people doing rear upgrades use the LWB e brake cable but my issue is my car already is a LWB so thats not an option does anyone have an idea for how to fix this? Could just cutting and extending the cable be possible? The phaeton caliper also looks like it positions the ebrake part of the caliper differently but can't tell if its beneficial of just makes it sit even further away.