suspension wise they share A8 components,

brakes are very cheap to replace, 360/365mm disks are £55ea cheapies, Brembo £130 set pads about 40-80 a set depending on quality

suspension airbags can be problematic and costly

As said the interior is nasty and nowhere near A8 standrads

top choice would be a late W12 Phaeton

bits are scarce and special order for everything, used stuff are like chickens teeth
A8`s on the other hand....... plentiful

just my 2 penneth ofcourse