Not a fan of this speculative photoshop.
It is interesting the article talks about BMW considering:
1) M variant of the 6er Gran Coupe
2) Also considering a 3er version of the Gran Coupe as a replacement for a M3 sedan. My best guess would be something similar to a 35is in terms of power but with CLS styling. It would sit above the 35i sedan but below the M3 coupe in terms of performance. I think it would be a big hit if they made it.