The next-generation BMW 4 Series coupe has been spied during public road testing in Germany.The 4 Series prototype seen here seems to have a sharply angled shoulder line which jumps down dramatically after the front wheel arch and steps up again prior to the rear wheels.There are numerous false body panels fitted to the side of car, so it's very likely this design element is an elaborate ruse.Thanks to its comprehensive camouflage kit it's hard to see too many of the car's styling details, but the coupe's headlight and tail-light graphics are clearly visible.Under the skin, the new 4 Series rides on the same CLAR platform as the latest 3 Series sedan and wagon. This should mean the new coupe is not only lighter than the current model, but have keener handling too.Drivetrains, in the form of turbocharged four- and six-cylinder engines, will likely be shared with the 3 Series range. Given tightening emissions rules and a swing in consumer preference away from diesel engines, a plug-in hybrid model is highly possible.All-wheel drive will be available as an option or as standard on some variants.As with the current 4 Series, the next-generation will be offered as a coupe, convertible and five-door Gran Coupe liftback.We know BMW is also preparing an all-electric i4 model, which from earlier spy photos looks to be a lightly restyled 4 Series Gran Coupe.MORE: 4 Series news, reviews, comparisons and videosMORE: Everything BMW

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