No one was guarding the BMW X6 M this morning, so we hopped the barrier and snagged shots of its twin-turbo V8. That and the 180 MPH speedometer... in a 5,247 Lb SUV.

That 180 MPH speedometer is no joke either, equipped with the optional "M Driver's Package" both the X6 M and BMW X5 M will hit 171 MPH.

Here's what BMW has to say about the engine:

Both the BMW X5 M and the BMW X6 M come with a new V8 high-performance power unit boasting performance features precisely tailored to the character of each model. Displacing 4,395 cubic centimetres, the engine delivers maximum output of 408 kW/555 hp from 5,750–6,000 rpm. The new M TwinPower Turbo engine is indeed the world's first power unit with a common exhaust emission manifold joining both rows of cylinders as well as Twin Scroll Twin Turbo Technology. The turbocharger and the catalytic converters are positioned in the V-section between the two rows of cylinders ensuring the spontaneous and direct response so typical of BMW M as well as a linear surge of power for a consistent flow of torque at all times. As a result, peak torque of 680 Newton-metres or 501 lb-ft is maintained consistently all the way from 1,500–5,650 rpm.

And here's the performance figures:

Performance and fuel consumption of the BMW X5 M and BMW X6 M:
Acceleration 0–100 km/h: 4.7 seconds
Top speed: 250 km/h (155 mph) (275 km/h (171 mph) with optional
M Driver's Package)
Average fuel consumption in the EU cycle: 13.9 litres/100 kilometres
(equal to 20.3 mpg imp), CO2 emissions in the EU cycle: 325 g/km.