If that is correct, it could be due to the soft top, there's no place for them to mount the Satellite Radio antenna? My Jeep Grand Cherokee came with factory Sirius, and the roof antenna is a little large -- I wouldn't want that piece anywhere on my Viper. You can do it yourself and add satellite radio to your existing radio, placing a small antenna in the front center of the dash, behind the windshield. We replaced my factory radio with a Chrysler RB1 nav radio, and added XM radio via a Terk XM-Direct unit. Before we did that replacement, however, we confirmed the Terk XM-Direct worked OK with the factory RBQ radio.