I think this is awesome.
Engines that would be sweet that won't happen-
S65 V-10
FI S54 because who doesn't love the S54.
The TT V8 from the new M5/6
But, we all know it's going to be an overboosted N54.
My guess? 390hp. Not quite 400... but more than enough to put it above the 1///M and lower than the F30 M3 which will probably come in around 450hp (just a guess.)