FRANKFURT - Several outcomes remained possible to a power struggle pitting Porsche SE against Volkswagen a day ahead of an expected showdown between the carmakers' rival factions, people familiar with the matter said.

At stake is control over the carmaking powerhouse set to emerge from any deal between the two, an issue that has split the extended clan that owns Porsche.

One day ahead of planned supervisory board meetings at both companies that could put an end to months of wrangling, there were still a number of roadblocks to be cleared, two people familiar with the matter told Reuters on Wednesday.

One matter the two sides still need to discuss according to the sources is a potential tax liability that a merger would create, which German media this week said could total 3 billion euros ($4.26 billion).

Porsche SE, the holding company that controls sportscar maker Porsche AG, needs to dig itself out of a debt hole and strengthen its negotiating position. It accumulated the debt amid failed efforts to seize full control of VW -- Europe's biggest carmaker -- that left it with a stake of nearly 51 percent.

The Porsche and Piech families -- which control all the voting shares at Porsche SE -- have been at loggerheads for months over how to resolve its debt woes and the role Volkswagen would play in the whole deal.

A sale of Porsche AG to Volkswagen would help Porsche SE pay off most of its debt, which sources have said stands at more than 10 billion euros.

Porsche's Chief Executive Wendelin Wiedeking has been pushing a possible deal with Qatar that would give the Gulf state a 20 percent stake in Volkswagen via derivative contracts.

Meanwhile, speculation has been heating up over whether Wiedeking may be forced to leave the company, and sources said on Wednesday that the Porsche family's talks with the CEO over his possible departure were in their final stages.

Porsche, however, said that Wiedeking was set to present his concept for the company's future to the supervisory board on Thursday.

It also remains unclear whether Ferdinand Piech, a co-owner of Porsche and chairman of Volkswagen, would support the plan to strike a deal with Qatar. He has been pushing a rival idea for VW to buy a minority stake in the Porsche group's healthy Porsche AG sportscar business.

Shares of Volkswagen were 2.2 percent lower at 244.00 euros by 1058 GMT, while Porsche's stock was up 1.2 percent at 51.08.

(Reporting by Hendrik Sackmann and Philipp Halstrick; Writing by Maria Sheahan; editing by John Stonestreet)

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