Louis G. 
2011 BMW 3 Series Diesel 335d 4dr Sedan (3.0L 6cyl Turbodiesel 6A)
Best 4 door sedan ever made *
 No other 4 door sedan has ever offered the blend of performance, comfort, fuel economy, and driving enjoyment that this car does.  36MPG, 425 lb-ft of torque, a 550 mile range, comfort, handling, etc.   It really does have it all.  The question you have to ask yourself is, do I feel comfortable turning a wrench from time to time? Is this car reliable? No.  No it's not.  Get yourself a good code reader, spend time on message boards learning about the car and you can manage most repairs on your own if you are a decent backyard mechanic.    If you keep up with the maintenance it will reward you with a sort of relaxed confidence that only an engine like that inline 6 torque monster can provide. You don't need to rev it out.    By 1800 rpms it's at a full boil and the asphalt starts to ripple as the mountain of torque is released.   No fanfare, no screaming engine, just a light rumble and off you go.   Its comfortable enough to drive all day and has the fuel economy to drive from Philadelphia to Boston AND BACK on a single tank.  Seats 4 adults comfortably.  Headlights that light up a stadium, a stereo that has a rich full sound.  I mean it really does have everything.    Don't say I didn't warn you about the reliability .     One more thing.. .once you get to about 150k miles or so, the particulate filter will reach the end of its life. The dealer will want 3000 dollars to replace it.   There are other options if you look into it a little.