The BMW 4 Series Gran Coupe was spied recently for the first time out in the open. The BMW 4 Series prototype, which is completely camouflaged, was doing some initial test runs on the Nurburgring circuit in Germany. The BMW 4 Series is going to be a four-door coupe, just like the Mercedes CLS, but smaller. BMW will probably sell the new 4 Series with both petrol and diesel engines. So far, the exact date when BMW is going to premiere the 4 Series is not known yet.