DETROIT — Wall Street and Motown were abuzz early this week over national reports that General Motors and Chrysler were holding high-level merger discussions. Behind the scenes, Chrysler also is said to be pursuing similar discussions with Renault-Nissan, company sources told Inside Line. One Chrysler manager said Nissan, which already has agreed to several product-sharing deals with Chrysler, could take an equity stake in the company of as much as 40 percent.Chrysler is owned by Cerberus Capital Management, one of Wall Street's largest and most aggressive private-equity firms. Cerberus has been negotiating to buy the remaining 19.9 percent stake in Chrysler held by former parent Daimler.Cerberus also controls 51 percent of GMAC, the financial services company that provides loans for GM's dealers and customers. Reports in a number of national publications, quoting unnamed sources, said Cerberus has offered to swap its stake in Chrysler for GM's remaining 49 percent of GMAC, with Cerberus maintaining a minority equity position in the combined automakers.Analysts debated the merits of combining the assets of two troubled U.S. automakers. The deal could enhance GM's near-term changes of survival, in part by giving it access to Chrysler's cash hoard, estimated to be around $11 billion. But the combined companies would likely stagger under the burden of massive debt, too many plants and employees and too many brands with too much product overlap.A broader deal with Nissan, analysts argue, would make more sense for Chrysler. There is less product overlap between the two companies, and their respective strengths tend to complement the other's weaknesses.An alliance between Nissan and Chrysler could also provide a potential pathway for the return of Nissan's French parent, Renault, to the U.S. Renault pulled up stakes here after selling American Motors to Chrysler in 1987. In 2006, Renault approached GM about a possible alliance but was rebuffed.Inside Line says: A GM-Chrysler marriage makes little sense, except perhaps as a short-term survival gambit. — Paul Lienert, Correspondent