Funnily enough, bought this weeks AutoCar Magazine last night and there is an article on the new M5, it then has a few pages on buying an old shape one.
Sevicing is very reasonable, £180 for a oil service and £280 for inspection 1, and £365 for inspection 2. Not too much different to my old SEAT Leon TDi.
They ran one for a year and was very pleased with it apart from some a/c problems, and sensor problems, which was put down to the short stop/start journies done evry day.
E90 320d M Sport Auto (Company car)
E91 330d SE Touring....Coming March