BMW’s future 4 series line-up will include a coupe and a convertible version, as well as their M4 variants, but the line-up still isn’t complete. The automaker is planning on bringing out a competitor for models like the Audi A5 Sportback and the upcoming Mercedes CLA. Image galleryWhat is their solution? A 4 series Gran Coupe that will follow in the path of the recently released 6 series Gran Coupe. The car will be based on the upcoming 4 series Coupe, but will get two more doors, a slightly longer wheelbase, and a set of usable rear seats.SAME ENGINESIts exterior design will be similar to the one found in the 3 series, but will add gaping air intakes and smooth aluminium style inserts for a more upmarket feel.Underneath all this, the automaker will be using the same engines found in the coupe version. This means there will be a choice of four engines - two petrol and two diesel - with the most powerful version being the 435i with an output of 228kW.BMW will also be offering an M4 Gran Coupe model that will be powered by a 228kW six-cylinder turbo engine. Expect to see the new 4 series Gran Coupe launched in 2013. Lots more Wheels24 spy shots.