The head of Volkswagen's Brand Group, Wolfgang Bernhard, vowed not to spare "sacred cows" in his drive to restore lustre to the marque.
"We have to look at all possibilities in order to face the challenges ahead of us," Mr Bernhard said in his first address as head of the division.
He spoke as one of the main players caught up in a bribery and fraud scandal at the firm had his resignation accepted.
Volkswagen chief executive Bernd Pischetsrieder will assume the functions of management board member Peter Hartz until a successor is found. A four-member steering committee took a preliminary decision to accept Mr Hartz's offer to quit.
He was in charge of personnel, contacts with the German government and Latin American operations.
German state prosecutors are investigating allegations that VW bribed employee representatives on the management board to secure support for unpopular measures aimed at restoring the group's ailing finances.
Overall, Europe's biggest carmaker is targeting savings and performance enhancements of more than ten billion euros (£6.9 billion) to improve its net profit by four billion euros (£2.75 billion) by 2008, a source close to the firm said.
Dubbed "ForMotion Plus" in a reference to Volkswagen's current ForMotion programme ending this year, the new efficiency drive targeted for 2006-2008 should allow the group to continuously improve earnings during the period.
Mr Bernhard said there were no plans at this point for any drastic steps such as shutting an assembly plant - a factory in Belgium is said to be a possibility - or pushing to change VW's onerous wage agreement with German workers, but the former star manager from Chrysler added all options were open.
"We will turn every stone on the way, nothing will be unchecked and there will be no sacred cows," he said.
He delivered a bleak message to investors betting on a more positive outlook.
Volkswagen stock closed down 2.8 per cent at 39.69 euros.
"The recovery of the sick patient VW brand is likely to take longer and will be more difficult than the consensus in the financial community so far anticipated," analyst Robert Heberger from bank Merck Finck said in a note to clients.
As VW's powerful works council reels over accusations of cronyism, the shares had hit a high not seen since January 2004 on speculation that Mr Bernhard might seize the chance to implement unpleasant changes.
"Investors are mistaken in thinking it will get easier to push measures past the unions following the scandal. After accusations that the works council was too friendly with management, IG Metall will strike a hard-line stance to regain credibility among the work force," said Heino Ruland, head of research and sales at Frankfurt brokerage Steubing.
Deteriorating net pricing, a weaker dollar and a mass model offensive that effectively ended with the launch of the Passat saloon would mean the VW brand needed to boost gross earnings by seven billion euros (£4.82 billion) to reach an acceptable return, VW said.
Mr Bernhard is not going to push to change an accord that guarantees jobs through 2011.
