It was an option. If you want XM you can add the needed receiver and antenna. I think there's also an aftermarket Sirius receiver that's integrated too (uses existing radio controls).

I used to be a big XM fan and found that I listened to my XM portable with boombox and home dock more than any of our integrated car systems. Check out the add-on units with their own control panels that you can take with you too. They could be a better value for you depending on your listening habbits.