I have a 2011 135i 6MT (N55) with only slightly over 7000 km and have always gotten at least 450 km out of a tank, if not more. On the highway, averaging about 125-130 km/h, I can get close to 600 km on a tank.
I followed the break-in procedure and use Shell V-Power 91 Octane almost exclusively.
I've also been to TO 3 times since I got my car and even in dense TO traffic I would not drop to 400 km/tank.
You guys must be having a LOT more fun with your cars than I am. I guess I just need to push it harder, but then again I'm usually with my wife and she doesn't appreciate such behavior.
