There is no doubt that 2012 turned out to be one of the toughest years for over 20 passenger vehicle brands in India. One auto brand that has not only bucked the trend, but also ended the year with a stunning performance, second time in a row is Audi. After a strong 84% sales growth in 2011, and around 56% sales growth in 2012, the German luxury carmaker is hopeful of becoming number one luxury car brand in…