V8 turbo should have its debute in X6. So X5 should get its performance version with same engine just after that. That is the plan but could be changed.

Regarding 4.4L petrol: N54 I6 bi-turbo engine produces 306PS (333PS in "si" variant), while 4.8L V8 has an output of 367PS (and there is still some room for boosting the power output).

But there will be a 4L+ NGV8 engine - with an output of 350+PS, while the turbo version will produce 400+PS. The plan is to premiere them in X6 and new F01 7-series.

But could it be BMW are speeding up the development of NGV8 for E70 & 5-series / 6-series facelift? No comments on that as yet.