The X5 4.8is is nice and all, but it is not all that different from its predecessor, the X5 4.6is.
I don't think it is going to be big news, given that the Cayenne Turbo still has more power (albeit in an ugly design) and the X5 platform is due for a redesign, not to mention the big SAV news for BMW is the launch of the X3.
So, I don't know if there is anything that really needs to be announced.