So which one is what? Here it is laid out:
F30 - 3 series sedan
F31 - 3 series touring/wagon
F32 - 4 series coupe
F33 - 4 series convertible/cabriolet
F34 - 3 series GT
F35 - 4 series 4 door coupe
Confusing? A little bit, but also redundant. No need for a 4 series, the 3 series has always had coupes. The 5 series GT was already a failure, why they want to repeat the mistake we do not understand. The F34 and F35 are redundant although the 4 door coupe segment does seem to sell. However, that was with more upscale models such as the CLS and Audi A7. BMW seems intent on filling niches that don't need filling, but hey, if they didn't learn their lesson with the 5 GT...