US carmaker General Motors and French auto producer PSA Peugeot Citroen have provided details on what exactly their planned alliance will look like. It will include the joint development of cars and purchase synergies. General Motors of the US and PSA Peugeot Citroen of France on Wednesday announced details of their plan to forge a strategic automobile alliance in the years ahead. Cooperation between the two carmakers would include the joint development of four vehicle models for Opel/Vauxhall as GM\'s European division and Peugeot, the auto makers said in statements in Paris, France, and Rüsselsheim, Germany. GM and PSA also reported they would create a joint technological platform for low-emission compact cars. In addition, the two companies would pool resources in their purchasing strategies. Peugeot in crisis mood Closer cooperation between GM and PSA will result in annual savings to the tune of $2.0 billion (1.54 billion euros). The companies said the scheme could be fully implemented within five years. French carmaker PSA confirmed the government in Paris was increasing it up to 7.0 billion euros in financial guarantees. The offer came as the ailing carmaker announced yet another slump in sales. It said third-quarter revenues dropped by 3.9 percent, adding that Peugeot was closing one factory and planning to lay off thousands of workers.