The fact that there is now an SUV in the BMW M line-up opens a door to a whole lot of new possibilities, including the potential of a high performance M diesel SUV or a high performance diesel version of the X5/X6 that’s as powerful as M cars but without the badge, if they want to keep that last remaining bits of exclusivity.

After all, even though the Cayenne Diesel has specs that are abit of a bore, the most powerful Audi Q7 is the Audi Q7 V12 TDI.

The latest rumours to hit the web is the development of a tri-turbo diesel for this high performance diesel BMW X5 which could produce 354 horsepower and nearly 800Nm of torque. BMW’s star diesel powerplant right now is the all-aluminium N57B30 which makes 245 PS and 540Nm of torque.

Its most powerful diesel is a V8 from the E65/E66 745d, making 329 hp and 750Nm of torque. The tri-turbo diesel could slot above the 730d as an upmarket diesel model in the new F01/F02 7-Series. But all of these figures are still short of the Q7 V12’s 500 PS and collosal 1000Nm.

Tri-turbo engines are not new, though I’m not sure if any made it to production there are companies who have showcased concept engines. One of the more recent examples that also so happens to be a diesel is the concept Mercedes-Benz SLK320 CDI Tri-Turbo which had a V6 diesel engine with 2 small turbos that connected to 1 large turbo. It made 286hp and 628Nm of torque. It never went into production because engineers said it was too expensive.