The model is catching the 7 series fast and Fintan Knight, head of A8 product marketing, believes the A8 can take pole position this year.
According to the German Federal Motor Vehicle Registration Agency, 4,197 BMW 7-series models were registered in Germany during the first seven months of the year, while Audi sold 3,985 A8s during the same period.
It was a similar story in western Europe where 6,391 7 series were sold during the first half, according to Polk market research, while Audi sold 6,149 A8s.
Knight believes that the 3.0-liter diesel A8 will bring the model an increase in unit sales. The model, available since March, is being advertised by Audi as "the world's strongest V-6 diesel".
The car was the first full-sized diesel to comply with Euro 4 emission regulations without the use of a particulate filter.
Knight hopes to sell up to 4,000 3.0-liter diesels a year, 50 percent of them in Germany, the largest A8 market.
Knight said that the A8 is already a success in the eight-cylinder segment, where it is the European market leader according to Polk with 3,771 sales ahead of the BMW 7 series (1,829) and the Mercedes S class (1,819), during the first half of 2004.