 Never, EVER buy a 3.0 6 cylinder diesel BMW.  Fortunately, I purchased the 5-year, 100K factory extended warranty for my 2011 BMW 335d, and boy-of-boy did I ever have to use it -- A LOT!  This diesel engine is absolute crap.  Had every fuel injector replaced at least once (a couple 2x) before hitting 45,000 miles.  The car was out of service so often that I got to drive a number of other BMW products from dealer, most of which were no where near as nice or had performance as good as my other vehicles (Jaguar XK, Chevy Tahoe Z71 4x4, Jeep GC Overland 4x4 diesel).  I bought the 6 cylinder BMW diesel based on a recommendation from a friend, in England ("John"), who told me that loved his (at the time).  However, several months after I bought my diesel, John told me that his 6 cylinder BMW diesel engine had blown up (literally!) while traveling about 50 milers from his home, and this just a few days after it had been "serviced" by the local BMW dealer.  His vehicle had just gone off warranty, and neither BMW nor the dealer would givr him any compensation or other assistance for the defective engine.  Again, STEER CLEAR of any BMW 6 cylinder diesel engine -- they are "junk".