Sure, but remember, that was just an example. There are production engines making 150hp/L or more. It is not a stretch to think BMW can meet or exceed that figure.
I guess I just don't agree that the new Maserati engine is a very good measuring stick for what we can expect in an M3/M4. To me it seems arbitrary.
2008 Interlagos Blue E93 M3 - M-DCT
2011 Salsa Red Jetta TDI Sportwagen - DSG