The 2 Series Active Tourer is BMW's best seller in many European markets yet all of the brand's other even-number models are niche vehicles. Having just announced a facelift for the two-door 2 Series cars and a 6 Series GT as well as an 8 Series concept, there has also been news for the 4 Series, in the form of a mid-cycle restyle. That includes the fastest open-top variant, the M4 Convertible Competition.