In a timely deal, US digital satellite radio subscription company XM Satellite Radio has negotiated a deal with General Motors to include satellite radio receivers in most GM cars manufactured from 2004.

The company has faced money troubles recently, so the new deal, which guarantees a core base for subscription customers, has not come a moment too soon.

XM and rival Sirius are expected to battle for dominance of this mobile market as they scramble to increase their subscriber bases. Subscribers are the core of their business model.