BMW working on diesel X5
This is so far just a rumor but a fun one. In the game of one upping everyone, BMW may be thinking that two turbos may not be good enough for its performance diesel engine, so it bolted on one more on for good measure. Next to the X5 M, BMW may give its six-cylinder diesel with a tri-turbo setup delivering 354 hp.
To entice the eco-minds, BMW will also add technology like the Start-Stop system and Brake Energy Regeneration (KERS). The super oil burner will likely slot between the X5 M and X5 xDrive48i, and have the body kit to reflect it. This could include a more aggressive bumpers and flared wheel arches.
Source: BMW Blog