BERLIN, Germany - Audi has opened a "digital" showroom in central Berlin, part of a shift by luxury automakers to display vehicles 'virtually' as they move into smaller but more expensive central locations to woo young affluent buyers.The showroom, on Berlin's grand Kurfuerstendamm, is a quarter the size of a conventional showroom and displays only four models but Audi says that allows time-pressed people to view and configure cars from Audi's full 49-model range on multimedia screens - no test drive needed.GERMAN AUTOMAKERS GO DIGITALIt's a strategy also being embraced by German rivals BMW and Daimler's Mercedes-Benz as, after a six-year European market slump, such companies overhaul sales practices and look for new ways to attract customers.Audi's head of sales in , Wayne Griffiths, said: "Staging the brand is becoming so much more important."The digital showroom is VW-owned Audi's third - the others are in London and Beijing - and is close to Apple and BMW stores. Like its German rivals, Audi has the challenge of displaying an ever-growing model and technology portfolio in city centres where space is scarce.Hence the smaller 375-sq m showroom and the focus on virtual demonstrations and the personal touch of a car dealer and a customers'lounge.AUDI TO OVERTAKE BMW?Audi is attracting 8000 visitors a week to its digital showroom in Beijing which opened in January 2013. Its London-based store, launched in July 2012, is drawing 60% of customers new to the brand.Audi has pledged to overtake BMW as the world's biggest luxury automaker by 2020 and shrank the sales gap with its Munich-based rival to 80 000 in 2013 from 85 000 in 2012. BMW outsold third-ranked Mercedes by 193 000 units in 2013 and 220 000 in 2012.While Audi still shuns internet-based deals, BMW is selling its new i3 battery car over the web; it will also take online orders on the new i8 battery sports car, due to reach dealers in the next couple of months.BMW has a series of brand stores in major cities such as Paris and New York and employs so-called "product geniuses" to help customers configure models online.Mercedes-Benz has a goal of more than doubling its 20 urban stores by 2020,when it also aims to retake the premium car sales crown from BMW.Stuttgart-based Mercedes started online sales of compact models through outlets in Germany and Poland in December 2013.