In actuality, the latter two are destined for US market, leaving S65 at
home in Europe. I suspect that the 2004 is the last year for the W220 so
Mercedes-Benz USA might find it not worth the cost of homologating the
S65 for US in its last year of production. However, Audi did it with RS6
on its last year before the new A6 is introduced in USA this autumn.
Please contact Mercedes-Benz customer service to insist on bringing S65
to the USA. Same with S400 CDI, too.