ONLY three manufacturers are taking part in the German touring car series this year: Alfa Romeo, who won it two years ago; Opel, who are still trying; and Mercedes - who not only took the championship in 1994 but are numerically superior in their efforts to win the prestigious title again. Last year's winner, Klaus Ludwig, a dour, seemingly always complaining German, has dumped Mercedes in favour of Opel and his old friend and team owner, Keke Rosberg, the 1982 Formula One world champion. A new challenge, says Ludwig. To date they are still struggling. Over at Alfa - British touring car champions last year with the fiery Gabriele Tarquini who is now relegated to the Italian series - the team has a number of quick drivers, including Ferrari test driver Nicola Larini and Sandro Nannini, the ex-Grand Prix driver whose arm was severed in a helicopter accident a couple of years ago, but who has made a miraculous recovery to become a serious front-runner. But it is undoubtedly Mercedes which has the star drivers, including Scotland's Dario Franchitti and last year's top Formula Three driver, Jan Magnussen from Denmark. Franchitti, just 22, stole an amazing pole position first time out and then went on to win one round of the inaugural International Touring Car championship at Mugello in May. Magnussen has so far not shone but feels his forte is more in single-seater racing cars than in these rapid but heavy saloons. Mercedes' racer is based on its ultra-successful C-class executive saloon. Executive it may be to the rest of the world, it is a taxi to the Germans! Staid, boring and almost anonymous, the C-class has outsold anything else in its class, but stick on a set of slicks, lower the suspension, update that magnificent engine and it is almost unbeatable. Other drivers in Mercedes - which should guarantee a title victory come the end of the season in October - include Jorg van Ommen, the rapid German Ellen Lohr, as well as the quickest of them all, ex-Grand Prix star, Bernd Schneider. The C-class has, in Hong Kong, proved to be every bit as successful as it has in other markets, despite the recent downturn in car sales. With a choice of engines and a number of trim options, there is, it appears, a C-class for everybody. The lowest priced model is the C180, which starts at around $500,000, while the top of the range C280 Sport will set you back about half as much again. The 180 comes with a rather pedestrian, four cylinder engine and cloth upholstery. But leather and six cylinders are available further up the range. The price for a new C-class includes a three-year warranty and full maintenance - including parts and labour. Much of Mercedes' racing success must be due to its advanced double wishbone front, and multi-link rear suspension. Without doubt, the suspension on a C-class is one of the most sophisticated available in any saloon car. Only mid-engined super-cars could compete in terms of cornering. Twin SRS air bags are fitted, as are side impact beams. The front seat belts feature pre-tensioners and, apart from the base model C180, the front seats are electrically adjustable. Anti-lock braking is of course standard on all Mercedes these days. But it may surprise you to know that it is also mandatory in the German touring car series, as is unleaded fuel and catalytic converters. Who said racing cars bear no resemblance to their road-going counterparts? If, as is expected, Mercedes takes its second successive German title, feel safe in the knowledge that any lessons learned on the track may well be applied to the next generation of taxis. Sorry, executive saloons.