This plug-in hybrid is significantly quicker than the 20i. BMW says it will deliver around 30 miles of pure electric power from a full charge – but expect more like 15-20 miles in real-world driving conditions. The pace and range is almost identical to that of its main plug-in hybrid rival, the Audi Q5 TFSI e, and low company car tax is a major benefit. It's ultra quiet in electric mode, and even when the engine fires up its very peaceful. It'll also prove super economical to run if you can keep the battery topped up, but expect the MPG to be no better than the mid-30's when running on the petrol engine alone.