1. Other than renders, nobody has seen what it looks like.
2. Other than speculation, nobody knows for sure what the engine will be.
3. Other than guess-timating based on the M5/M6 suspension/tires, etc., nobody knows what it drives like, handles like or sounds like.
4. And other than rumor, none of this will be known until the Detroit/NAIAS Show in January 2014.
So I will take a pass at answering this until I know. In the meantime, I will enjoy, and will probably keep for a long time, my E92/M3.