I went to the Audi website and it is not clear.

Are they the same size? What else is different?

 

i think the s8 is v10 and the a8 uses the vw w12

as far as i know there the same size

 

I am confused.

The A8 has the more powerful engine?

 

well probably the A8 are much powerful than s8. I think they have the same size also.

 

depends on which A8 you get... if you get a 4.2, then no... if you get a W12, then yes... S8's V10 is just supposed to be higher revving allowing a little better performance under certain driving conditions...

 

the S8 has a sport suspension and little extras such as appearence and performance extras.

 

The S8 has the lambroghini V10 from the Gallardo.
Carbon fiber interior, lighter weight, stiffer suspension, bigger brakes etc.
The W12 engine in the A8 doesn't feel that much faster than the 4.2L surprisingly.

 

the tranny ratios are closer.
ex: at 77miles an hour a8 2200rpm approx. and the s8 3000rpm

 

A8 W12 versus S8....which performs better in each of these categories.

1> Handling

2> Acceleration

3> Speed

4> Traction

 

All four go to the S8, this coming from someone who has driven both of them.
The W12 is packing almost 500 more lbs, plus the suspension isn't as stiff as the S8's.
Traction isn't an issue on any audi other than the FWD A3.
The best way to sum it up would be to drive both of them, i think you'll agree the A8 W12 is the ultimate in luxury and it drives fast, but it doesn't put you back in your seat. The S8 is like a sports car in a long wheel base luxury sedan, if its performance you want, then the S8 wins that race.

P.S. the W12 A8 comes with a frigerator in the middle of the back seat with TV screens in the back headrests as standard equipment. We usually throw in a couple of wine glasses and a bottle of wine at my old dealer.