With automotive companies gobbling each other up Pac Man style, Tokyo is buzzing with rumorsAG is poised to take over Motor Co. Ltd.'s small 4.5% stake in Subaru-maker Fuji Heavy Industries Ltd. Of course, speculation surrounding such mergers pop up every week now that Corp. and Daimler-Benz AG have announced marriage plans and Volkswagen AG has gone on a buying binge. But this one may make more sense than most. Nissan, its sales and market share slumping in the U.S., desperately needs capital - no longer easily available from Japanese banks - to fund its next generation of models. For its part, BMW would gain a strategic presence in Asia. There's also potential for some fit on the product side. Subaru's lineup could slot neatly below BMW's - and the Japanese carmaker is strong where BMW's Rover subsidiary is weak or non-existent. That includes the U.S., where Subaru conceivably could add Rover models to its dealer showrooms. BMW also could help Subaru significantly increase its presence in Europe. Predictably, both companies deny the rumors of a tie-up. But as a source at Japan's Ministry of International Trade and Industry says, "If it isn't happening, then it needs to be."