We drove the 2017 Audi R8 on the banks of Daytona; the second Aston Martin Vulcan arrived in the U.S.; and we learned the difference between diesel and gasoline engines. It’s The Week in Reverse, right here on Motor Authority. The Audi R8 is a world-class supercar, and Daytona International Speedway’s road-racing circuit offers big speed as well…