I saw these at Habberstad in NY today, they look ok... I walked right passed both of them and didnt even notice them at first, never done that to an M car before... and I still dont understand the point of turbo charging them.
They dont even get good mileage for all the extra trouble. The EPA is 12 and 17, the M5's NA 10 cylinder does that for the most part. Why not just put a regular naturally aspirated 8 or 10 cylinder in there, keep the high redline, and the legitimacy of the brand image...?
Seems like purely green-ish marketing to me...