That's an interesting observation. Obviously it doesn't take 20 sec for an A8, but you really need to pay a lot of money for it to have a reasonable acceleration of ~5 sec. And I think this is the most striking thing about Tesla's cars, because right now, every potential Audi buyer knows that every single Tesla car will beat the 5 seconds 0 to 60 you bought with a lot of money (speaking of mainstream models).