Some oil on the fire...
I read something on a German forum and someone was saying the following; The M2 CS is coming this summer and will replace the normal M2... The M2 GTS wil be coming in 2018 as a limited production run... Who know what is true...but a M2 CS and GTS seems not realistic in my opinion... Maybe a M2 wit some kind of competition package (like the M3/M4) but those package are mostly available after the release of a GTS model (or CSL model).