The luxury car market is full of serious discounts this month and leading the way is the German trio. Mercedes-Benz, BMW and Audi are offering selected models at prices difficult to resist.Leading the way is Mercedes-Benz with the E200 CGI. The premium saloon is being offered with a Rs 5.5-lakh cash discount and a petro card worth Rs 2.5 lakh (3,500 litres approximately). This adds up to a