MOST cars sold in Hong Kong are equipped with accessories including stereo radio/cassette players and CD players. Even the wheels of many top models are light alloy, previously the most popular accessory purchased. Several so-called sports models come complete with aerodynamic appendages, even if a few are somewhat suspect in their efficacy. A number of manufacturers, however, are recognising the demand for slightly more professional additions and have set up subsidiaries to develop and market aerodynamic and performance-related accessories. Hong Kong has three such outlets: AMG Mercedes, which is sold through Zung Fu's Speedline company; Mazdaspeed, the performance arm of Mazda Motor Corporation; and Nismo, the tuning division of Nissan. Nismo is the most recent addition to the tuners and follows Mazdaspeed in offering aerodynamic kits, which include front and rear wings, side skirts and wing extensions. Performance parts include uprated shock absorbers, sports mufflers and a range of leather-rimmed steering wheels. More serious items include oil coolers, competition clutches and limited slip differentials. A natty line in sunglasses is available from Nismo for the less obsessive driver. Mazdaspeed, winners of the 1991 Le Mans 24-Hours classic endurance race with the Mazda 787B, rotary-engined sports car, opened its first overseas outlet in Hong Kong in 1994, with a range of accessories for the popular Mazda 323 Astina; the MX-6 sports coupe; the MX-5 open sports two-seater; and the top-of-the-range rotary-engined RX-7. As with Nismo and Nissan, Mazdaspeed offers tuning kits and aerodynamic packages, while there are competition clutches, uprated suspension components and harder brake pads available for the four Mazda sports models. The aerodynamic kits available for the four cars improve the appearance but also actually contribute to the vehicle's air penetration and the downforce created at speed. As well as the motoring accessories, Mazdaspeed sells a range of casual and sportswear, including sweatshirts, team caps, driving gloves and sunglasses. Leather wallets, key cases and racing stickers are also available. Mercedes first teamed up with the German tuning concern AMG in 1971, when it successfully put a racing touring car on to the track. This car was based on the Mercedes 300SEL and its success led to an on-going relationship which endures today. The benefits of touring car racing ultimately filter down to more humble road-going Mercedes and the range of models which can be customised with AMG parts includes the recently launched E-class, with its radical (for Mercedes) new lines and asymmetric headlamps, the C-class, of course, and the top line S-class saloons and sports models. Wheels are one of the more popular AMG accessories sold by Speedline, with an extensive range to choose from, while front air dams and boot spoilers are immediately identifiable as AMG parts. AMG Motorenbau und Entwicklungsgesellschaft mbH, to give it its full name, is more than simply a provider of bolt-on goodies. The company has its own engine shop and can offer enlarged, high performance power units for almost the entire Mercedes range. It also produces limited edition, high-speed AMG sports tourers, based on original Mercedes models. Speedline is in Leighton Road, Causeway Bay, while Mazdaspeed is in the Hyde Centre, Gloucester Road. Nismo is in Ap Lei Chau, opposite Aberdeen.