I drive a 2012 E91 328i xDrive Touring (curb weight >3700 lbs).
I get <10L/100km with *CITY* driving in Vancouver, and <7L/100km on the highway.
I'm neither a hypermiler nor a slow driver -- my driving style is fast but very smooth and steady, the primary motivation being to minimize wear and tear on the car. I intend to keep it for 10+ years unless something goes wrong with it.
Keep in mind too that I'm putting in 91 octane (AKI) premium gas. I was using 87 octane for a while, but that gave me about 10% worse mileage, so I figured just go with premium.