Good plan. That is what I guessed in post #6.

Will we see a sunroof delete and a carbon fibre roof?

I think if the X5 M and X6 M are identical in therms of engines ,speed and all the high tech stuff like DPC/ because now the main difference between X5 and X6 is exactly the R6/V8 bi-turbo and DPC-Dynamic Performance Control/ the X6 will loose its image of sport version of X5 and many people will loose reason to buy X6 instead of X5. Even now is difficult to argue the people why to buy the X6 because they are basically the same vehicles. I think that this will end with lowering the sales of X6 and ended its production. The X6 must be more individual and more sportier version of big SUV like X5 to keep interest in people/X6 Hybrid is good move/. I think that there is no real reason to make the X5 more powerful than X6 50i, give the X5 V8 bi-turbo but don't mess it with M badge, and make one truly impressive M model of Xseries - X6M.

My guess is that there will be a slight difference in the weight comparo between the ///X5 and ///X6. About 100-200kg's, to the ///X6's advantage. Cayenne killer.