The Smart ForFour (2015-) is a four-door four-seater city car. But unlike the first-generation version this is basically a stretched ForTwo model. A choice of two three-cylinder petrol engines is on offer: a 70bhp 1.0-litre and a turbocharged 89bhp 0.9-litre. But which, if any, is a good option? Read our full review to find out.