Our spies have spotted BMW's facelifted X6 undergoing testing in Europe. Virtually production-ready, the prototype has a revised fascia, new headlights and restyled taillights. Petrol engines will likely be derived from the current model, but rumours suggest a new tri-turbo 3.0-litre six-cylinder diesel could be added to the lineup. The new diesel powerplant is expected to produce between 258 and 294 kW. The facelifted X6 will be released in 2012. Check out our gallery!