Originally Posted by benzy89
Hoping this is sarcasm..... Obviously no incentive to buy a reinforced N55 that's rebranded as an "M" motor. Good knows the M division never would've been as successful if that's what they did from the start.
You seemed to have missed the part about the "innovative turbo setup". This is exactly what differentiates the S63 from the N63 today (along with more boost, higher redline, etc.). So the same transformation is possible for the N55 to an S55.
Furthermore, in fact, most M engines have been based upon normal series engine. This was not true of the S65 and S85, but before these it was the norm.