Radio reaches final frontier with XM band.(Chicago Tribune)

CHICAGO _ Satellite TV has been joined by satellite radio.

Satellite radio, like satellite TV, is considered one of the wonders of the electronic world, because it can add 100 channels to your dial.

However, only about 40 percent of the satellite channels are commercial-free, so while you escape the AM and FM routine, you won't escape the slew of interruptions.

General Motors began offering XM satellite radio for `02. Volkswagen will add it in `03, Chrysler in `04.

We tested an `02 Cadillac Seville STS, which along with the Seville SLS and DeVille DTS/DHS, offer it now.

For `03, GM will add it to 23 nameplates at Buick, Chevrolet, Olds, GMC, Pontiac and Cadillac, ranging from the Chevy Cavalier economy car to the Cadillac Escalade luxury sport-utility vehicle.

As always, the STS proved rich in amenities as well as room and comfort. Solid …