During the last three decades the tuning sector has become a sizeable branch of the German economy. A survey of the Verband Deutscher Automobil Tuner (VDAT) in 1994 recorded about four hundred businesses directly connected with the tuning sector. From 1994 to 1998 total turnover in the tuning industry showed an annual growth rate of just under three per cent. Compared with a 1994 turnover of 7.0 billion marks, latest estimates of the 1998 figure showed a total industry turnover of 7.7 billion marks. More recent figures are not yet available. A positive trend was also forecast for the year 1999 and estimated to be between two and three per cent to reach a figure of approximately 7.9 billion marks. This positive balance, however, is not exclusively generated by the tuning businesses, part of it is contributed by the manufacturing industry. Low-profile tyres (aspect ratio < 60) sold by the tyre manufacturing industry, for instance, are incorporated in the figures. Until the seventies the dominating theme in the industry was optimisation of engine performance, but during the last 20 years the tuners have more and more concentrated on a complete personalisation and harmonisation of the vehicle. In this context tyres and wheels take a decisive role, since this product group with its 27 p.c. turnover share in all VDAT member companies can claim the largest slice of the lucrative tuning cake.