A SF Chronicle writer tested out the Sirius satellite radio service and found it similar to the XM system he tested in November. The main difference was that he installed the XM himself in a 1993 Chevy company car, whereas the Sirius system he tested arrived preinstalled in a new BMW X5 SUV. We now know who’s putting their PR money where it counts. Both have CD quality sound, decent coverage, and similar station lineups. Sirius is a little more expensive because it is commercial-free. Both are using ground repeaters to enhance coverage; XM has many more since it has one less satellite up there. Will we soon be buying radio the same way we buy cable/satellite TV? (for satellite radio news, check out the SatRadio weblog)