This combo picture shows an XM Satellite Radio unit (top) and rival Sirius Satellite Radio unit installed in separate private vehicles in Washington February 20, 2007. Would a merger between XM Satellite Radio and Sirius Satellite Radio be good or bad for the music business? That's the question industry executives have been wrestling with since the two companies announced plans to combine in a $13 billion deal that creates a single satellite radio behemoth. REUTERS/Jason Reed