BMW will be making the most of its new 3.0 liter, tri-turbo diesel unit as BMW Blog now reports the engine will be available in the 5-Series too.
The M550dx nomenclature came from a leaked supplier form for a model we have not seen before. The M-Sport Package 5-Series diesel (with xDrive) will likely feature around 400 PS (294 kW / 395 bhp) to maintain output at around the same level as the 550i (407 PS).
The new tri-turbo diesel, though, will first be introduced in the X6 xDrive50d model which will debut in March 2012. It will also be featured in the upcoming, facelifted 2012 7-Series in the 750d variant.