Cadillac Seville with XM Satellite Radio by Cordell Koland The auto industry has been on a technology binge transforming most of the functions and processes over that last decade. But with the exception of a few features such as automatic climate control and navigation systems, you¹d be hard pressed to distinguish a luxury car from the 1950s from a contemporary model on a short jaunt to the local mall. While the average luxury car is stuffed with the latest technology, most of it is invisible and almost undetectable to the driver. There is one new feature in the 2003 Cadillac Seville and all Cadillac models that should command attention from most owners, and that is XM Satellite Radio, a new subscription audio service. Radio has pretty much stood still in terms of technical advances since the advent of stereophonic broadcasts and the FM band, which features higher fidelity than the older AM format.  But before we dive into XM Radio, a word about the Seville STS. Although the Seville is the oldest car in the Cadillac lineup, it remains one of the most satisfying. A responsive V-8 engine delivers smooth power. The ride and handling are first rate. One could argue that the styling is dated, but I prefer its more subdued lines to the current Cadillac school of design with its stacked headlights and sharply creased horizontal character lines. As a long time audiophile, I found the sound quality of XM radio to be excellent on the high-end Cadillac system. Classical music was delivered with rich sonic detail. The technology behind XM has won awards from Entertainment Weekly, Fortune, Time and Popular Science magazines. XM is an all-digital radio band that features more than 100 channels. The technology is built around recent advances in sound transmission. The signal is processed by a special encoding technology and transmitted to two satellites that remain in a stationary orbit in relation to the United States and allow almost unbroken coast-to-coast reception. Repeaters in urban areas keep the signal strong, even in high-rise canyons. If XM Radio truly works as advertised, it could be a boon to long-distance travelers who are subject to large sections of the country with little AM or FM coverage. I only experienced a couple of signal losses. One was in a concrete multi-story parking structure and the other was on a section of road flanked by groves of very tall trees that created an enveloping canopy. The 100 standard channels available on XM radio cover an amazing variety of alternatives. If the music you like is recognized as any kind of commercially viable category, you will find it in abundance on XM. There are multiple channels for classical, rock, world, jazz, country and Christian music. There is a plethora of news and talk, covering a broad range of sources such as Bloomberg, the BBC, ESPN, CNN, ABC and the Weather Channel. There are also proprietary news and entertainment channels that deliver old-time radio, Christian talk, book reviews and African American news and opinion. Some of the original programming is distinctive to say the least. I caught a channel that features music from the 1940s. Between musical numbers, an announcer read news bulletins covering the war‹not the war with Iraq‹but events that occurred during World War II. XM Radio is available in most current models within the General Motors family, including Saab. Honda and Nissan will offer the service as a dealer installed option. Once the special radio is installed, the subscription runs $9.99 a month. Premium channels will also be available, although the choice is now limited to the Playboy channel, which offers saucy adult entertainment.  The remaining question is who would benefit from XM Radio. If the radio is standard equipment as in the Cadillac Seville, then the buyer has the option whether or not to subscribe. The monthly $10 cost is probably a no-brainer for most Cadillac buyers. On the other hand, a young buyer of a Chevy or Pontiac may have second thoughts. If you spend lots of time commuting or have the kind of job that keeps you on the road, the XM technology could be a real asset, allowing a huge selection of quality programming and impeccable sound quality.     Vehicle: Cadillac Seville STS Price as tested: $52,195 Engine:          Type: 4.6-liter V-8          Horsepower: 300 @ 6,000 rpm          Torque: 295-ft. lbs. @ 4,400 rpm Fuel economy, automatic transmission          City - 18 mpg          Highway - 27 mpg Curb Weight: 4,027 lbs.