Click on the image above for our high-res Concept CS gallery

With their scopes aimed squarely at the upcoming Porsche Panamera and Mercedes-Benz CLS, BMW's M performance division is rumored to be working on their own four-door luxury GT for a 2010 launch. With its styling based heavily on the BMW Concept CS (pictured above), the platform for the new flagship will be shared with the new 7 Series. Under the hood, most expect to see a 6.0-liter V12 based on the current M5's V10, or a twin-turbocharged V8 like the one rumored for the next-gen M5. Even though both of those engines promise prodigious amounts of power, and the lightened chassis will be tuned for performance, BMW insists the new car will not be badged an M8. Regardless, we seem to recall that the lack of an M badge on the mid-90's BMW 850CSi didn't seem to deter enthusiasts.