If true this is pretty disappointing. But its not like we didn't see it coming. The writing has been on the wall for some time now.
To me, though, the most disappointing thing is not necessarily that future M engines will employ turbo chargers, or even that the high performance X6 (apparently anyway, according to this article) really will be an M model and not an "si". No, the most disappointing thing is that they are (apparently) just pulling the non-M N64 V8 off the shelf and applying more boost. I'm sure there will be other tweaks, but the engine itself will not be uniquely M. I was hoping that, if (when) M decided to start using forced induction, they would design their own engines (or start with the current S65/S85 as a basis) focusing specifically on retaining the M character. The aftermarket has been able to turbocharge past and current M motors without necessarily lowering compression or lowering redline. So presumably, with some R&D this could be done to a factory motor also. Maybe only the X6 (and X5) M models will get a non-M derived motor. I know the article claims otherwise, but hopefully this turns out not to be the case. I do understand that sharing parts with the non-M brothers helps keep costs down. But the penalty is likely to be an experience that is less true to traditional M ideals. It is also notable that AMG appears to be headed in the opposite direction as far as this issue goes, the 6.2L V8 was their first built-from-the-ground-up engine, and they will apparently continue to use it going forward.
On another note, this is the first I'd heard that the X6 M would be getting 500hp. Perviously, reports were that it would be somewhat less. So at least they are serious about matching the competition in power I suppose. Not that I'd ever buy an SUV anyway.
I suppose we can celebrate the fact that we will have the last of a breed, and perhaps the only M3 ever to get a V8 (at least for the forseeable future) since it seems unlikely they'd give the M3 the same motor as the M5. Although, its possible the M3 could use a smaller displacement version or just have less boost. Personally, if BMW goes this route, there will be a lot more to take into consideration when choosing my next car. Of course by then who knows what the automotive landscape will look like.
2008 Interlagos Blue E93 M3 - M-DCT
2011 Salsa Red Jetta TDI Sportwagen - DSG