Porsche said on Sunday they were withdrawing works teams from international sportscar racing next year because of concerns about rules and costs.  The German manufacturer won the Le Mans 24 Hours for the 16th time this year but failed to win a single race in a FIA GT championship dominated by rivals Mercedes. Porsche have won 12 world sportscar titles since 1953 and their departure could fatally wound the FIA championship which currently has only Mercedes confirmed for next year.  Mercedes won the title in 1997 and 1998.

    ``Although we plan to return to Le Mans in 2000, a final decision on the company's participation in these racing activities will not be taken until a later date,'' said a Porsche spokesman.  ``The board of Porsche AG is seeking a future-oriented, long-term motorsport policy. Stability of regulations and limitation of expenditure is all the more important as Porsche also supports customer teams and cannot accept any inflationary use of materials and resources.''

    Porsche was one of the founders of the world endurance championship in 1982 and returned to GT racing in 1996, racing cars identifiable with its production models and also supporting a number of private teams.  But the factory is now concerned that new Le Mans regulations will favour open sports prototype cars.  Porsche's withdrawal of works teams leaves factory drivers Allan McNish of Scotland, France's Yannick Dalmas and Germany's Joerg Mueller and Uwe Alzen looking for other seats.