Formula 1 might monopolise the mainstream motor racing headlines, but few Grands Prix attract even half as many spectators as the Le Mans 24 Hours. More than 260,000 made the pilgrimage to north-west France in 2015 and the turnout is likely to be similar this time. The main draw? A fierce tripartite contest between manufacturers with proven track records but contrasting approaches. Triumphant 12 months ago, Porsche is using a revised version of its 919 Hybrid in a bid to repeat that success. To counter this threat, World Endurance Championship rivals Audi and Toyota have produced all-new cars, potentially similar in performance yet very different in conception. Here, we peer beneath the skin of all three main contenders and analyse their prospects. Porsche will be chasing a record-extending 18th outright victory at Le Mans this year, while Audi seeks its 14th and Toyota – world champion as recently as 2014 – its first.