What is it?
We’ve already driven the range-topping BMW 435i convertible, now it’s the turn of the car which will make most of the volume - the 420d. Aside from the engine, this is much the same car; a lower, longer and wider prospect than the model it replaces, and one that continues to sport a retractable metal hard-top roof.
From launch, the familiar 181bhp 2.0-litre unit will be the only diesel engine available with the convertible, and its frugality affords the car 55.4mpg economy and 133g/km CO2 emissions in conjunction with the six-speed manual gearbox. Select BMW’s eight-speed automatic, and they improve to 58.9mpg and 127g/km.
There are five trim levels to choose from, starting with the SE sampled here (although not on UK roads). The mechanics of a life cycle change means the 420d ends up with more standard kit than its predecessor - including the current 3 Series’s large infotainment screen, iDrive controller, Drive Performance Control, 17-inch alloy wheels and heated front seats.
The price difference is a modest £495. But that still sees the model start at £36,675 - almost £2500 more than the equivalent Audi A5 cabriolet 2.0 TDI SE. The example tested also featured a number of options - BMW’s Professional media system, 18-inch wheels, adaptive suspension - hiking its final total to £43,850.