AUDI is charging hard at the moment, eager to rid itself of the ‘third German’ alternative title in a bid to play level with BMW and Mercedes-Benz. And in the middle of the new-model frenzy designed to help achieve this goal, we have the A4 2.0 TDI, a niche player with talents alluring enough to cement the range’s position as Audi’s best-seller. Combining the model’s quality cachet with the A3/VW Golf’s headline turbo-diesel engine in a price that undercuts its nearest luxury rival (Mercedes’ C220 CDI) by more than $11,000, the latest little Audi may have big things ahead of it indeed.