While Sirius has gained considerable ground in terms of subscriber growth, in the receiver department some may see the smaller satellite radio service's selection to be lagging that of its larger rival XM, especially in portability. That may be about to change, according to comments from CEO Mel Karmazin on Tuesday during a conference call. Karmazin said beta testing is under way for the "Stiletto,' the company's portable live satellite radio product, which it hopes to launch by the end of August.

Details of the unit were not provided, and it is unclear whether it would save selected songs in a similar fashion to XM's new live portables. Sirius' excitement over the product may be leading it to raise its end-of-year subscriber projections yet again; the company now expects to reach 6.3 million subscribers, up 100,000 from previous forecasts.