Here is an instructive fact. This sleek new Hyundai Ioniq 6 saloon sits on the same platform as the already launched Ioniq 5 crossover SUV. They use the same electric motors, the same battery packs. Beneath the skin they really are the same car. And yet, the Ioniq 5 in the same rear-drive ‘Ultimate’ specification has an official range of 295 miles, the Ioniq 6 some 338 miles. Why? It’s simple: the Ioniq 5 has a highly commendable drag co-efficient (CD) of just 0.29, the Ioniq 6, a freakish 0.21.