Overview: On this episode of Supercar MegaBuild, expert mechanics Shane and Dan have one of their toughest assignments yet. They need to try to convert an Audi R8 into a Gymkhana Grid contender. That means taking an exclusive, executive supercar and turning it into mean machine that can slip and slide its way around a car assault course. Time is tight and the pressure is cranked to the max. Have the guys bitten off more than they can chew?