They are calling it a different N number but saying its a 3 liter. I don't think any real specs have come out yet so there is no way to tell. Being a tuner car will depend on how they choose to lock down the ECU. I expect their warranty claim experience with the N54/54 will have something to do with that.
My opinion is not locking up the ECU is what I would do to get a lot of free marketing buzz on the car & yes the price will go up. M5 = $108K, M6 coupe same options = $120K. Don't think the spread will be the same but there will be a spread.