Big Big fan of the A8 and the S8...infact driven a 08 Audi A8 4.2 Quattro quite a few times...nothing comes close to it (except maybe the 4.2 VW phaeton)...
a very important fact:
Audi is owned by the VW group which also happens to own Porsche, Lambo, Bentley, bugatti, SEAT, and Škoda.
The Audi heritage can be seen in the Gallardo interior and ofcourse the S8 has the same engine as the Gallardo. The chassis (as per my knowledge) is common for Toureg, Q7 and Cayyene.
For A8 lovers do check out the 'merc killer' ad...
Audi Big Game Commercial 2011 - Release the Hounds - YouTube