Originally Posted by KoenG
Watch out, the 650i Xdrive has more output and consumes less fuell, without cilinder shut down! S6=225g COČ and 650ix=215g COČ so the consumption is less with only Valvetronic. The 550i will get this update also this year so the lagging position is only temporal.
Hmmm, the US spec 2013 650xi coupe get the same MPG as the 550i, 16/24 MPG.