I had a Sirius hooked up to my Discovery for a long time (now it is in my F-150) and I have to say it sounds very good just going through the FM Modulator. My new Horizon is going to come equiped with a Sirius unit and I'm sure it will be hardwired instead of transmitted, but either way, it works well in my opinion. If your using a modulator, it is absolutely necessary to make sure the station you are trying to modulate through has NO radio station transmitting withn a close proximity of the one you want to use. I look for at least 2 frequency's either way of the station I want to modulate on and have no problem. If your traveling though, you will have to change the modulator from time to time when you enter other areas that are using your frequency or one that is close.
2006 Itasca Horizon 40FD