I own a 2008 Bluetec. No exhaust fluid required but a special motor oil is required (A version of Mobil 1 that meets the MB spec.). I bought the car used with 93,000 miles 2-1/2 years ago. It now has a little over 160,000 miles. No engine maintenance except oil and filter changes. Did change the serpentine belt at 100,000 miles --- the old belt looked perfect and it is riding in the trunk, just in case. The local mechanic did a pre-purchase inspection and found oil weeping from the usual oil cooler gasket/o-ring and the dealer lowered the price $1,000 instead of fixing it. Now 67,000 miles later the oil is still weeping but not enough to add oil before the 10,000 mile oil change interval. The oil pools in the plastic belly pan so there is no dripping on the garage floor. There is a lot of labor involved in replacing the cheap part to stop oil leak --- I will not have it replaced unless the rate of leaking increases. I paid $17,000 for the car and I am very happy with it. I would make the same purchase if I had to do it all over again. There have been two repairs to the car since I bought it. One involved a loose electrical connector inside the driver's side B pillar that was causing a faulty "fasten seat belt" message. The other was a problem with the trunk latch which was replaced. The original owner replaced one lower ball joint and there were some sensors replaced very early in the cars life. This car is repaired by the book - no shortcuts. So, all other "repairs" have been recommended preventive maintenance items.