So the 4 series is replacing the 2-door 3 series making it the new 2-door version of the 3 series and the 4 series GC is the 4-door version of the 4 series, but the 4 series GC is not the same as the 4-door 3 series which means that while the 4 series is a 2-door version of the 3 series, the 3 series is not the 4-door version of the 4 series, because well, that would just be silly... and then there's the 3 series GT.
