Providing details about capital contributions and risk-sharing, Italian carmaker Fiat has "sweetened" its buyout offer for General Motors Corp.'s (GM) Opel unit and its UK brand Vauxhall, in its effort to go past rival bidders - Canadian car-parts maker Magna International Inc. and RHJ International SA, a fund with earlier holdings of private-equity firm Ripplewood Holdings LLC.

Interestingly, the improved Fiat offer came after the German politicians appeared to be inclined towards the Magna bid, which they said was closest to their "hopes and wishes."

About Fiat's new offer, Ferdinand Dudenhoeffer, director of the Center for Automotive Research at the University of Duisburg-Essen, said that it reflects the carmaker's desire to get hold of Opel's technology.

However, German Economy Minister Karl-Theodor zu Guttenberg - who is piloting efforts for finding a "viable" bid for GM's European operations - largely remains unaffected by any of the three bids.

Guttenberg told the Bild am Sonntag newspaper: "We must first have a high degree of certainty that the significant tax money we will have to provide is not lost. From my point of view, none of the three offers so far provides this certainty in a sufficient way."

Meanwhile, GM wants to sell Opel before the June 1 US government deadline for restructuring or facing bankruptcy, and will have the final say in the Opel bids!