By Sam TickellAt the forefront - Audi and Peugeot as major manufacturers are pushing the green racing trendsWithout a shadow of a doubt, sportscar racing led the green push in the motorsport world and made quite a few PR, competitive and positive business blows in 2008.Two features stand out – The Michelin Energy Endurance Challenge and the Green Challenge of the Le Mans Series and the American Le Mans Series respectively.