Originally Posted by Bavarian

There are actually many 4-door sedans that would be an upgrade to the M5 in my opinion.

You can start by calling in the direct competition...like the Benz E63 AMG and new Audi S6. Then you go up the ranks and find the Benz S65 AMG and Audi S8 (to those, BMW still does not have a competing model).

The beauty in these competitors, and what makes them an "upgrade" compared to the M5 is that they are all available with an automatic tranny. The Audis offer AWD, and S-cars and AMG-cars are just more civil in general daily driving.