Mounting the 665 on the fairing or handlebars will not effect the XM reception. The XM part of the 665 is a hockey puck size part that most people mount on top of the radio inside the cowling. If you are heading North or you ride in the mountains then the signal may not reach the XM puck. This would hold true for the weather radar and traffic alerts as both these signals are received by the XM puck. The XM puck is actually the XM radio and antenna all in one.
Jim
I have my antenna (the puck) mounted on the stereo head unit, up under the front fairing.....minimal problems with reception. But the few times that I have experienced it is when I'm headed north. Interestingly, my wife has hers in the same location and she gets reception even when I'm not getting reception. The same goes for when we're riding in the mountains. But that's when I just switch over to one of the CDs.....I mean that's what the CD is for.

As fas as the XM antenna (puck) being the radio.....I learned that one the hard way. Jim (hd-dude) set the GPS/XM up on both of our bikes (along with a ton of other work). But when I went to use the XM in my dually 4x4 up in the snow, I thought it was just a matter of buying another XM antenna since I already had service for the radio/gps.
I'm on the phone with XM for at least half an hour. They kept asking me for my radio ID number.....go to channel #1 and read the radio ID number to me. I did that, way to many times to count. Finally, I gave up and thought I'd somehow ruined my GPS/XM or was it the new antenna. Soon I learned that the radio ID on a Garmin 2730 Street Pilot is actually the XM antenna number that they were wanting. That would have required a whole new XM subscription.
Andy has beat them......he and Jim have devised an antenna mount that's quickly transferrable from one bike to the other. So he has one subscription for all five (or is it six now?) of his bikes!
He's crossed over, too. Not worried so much about the look good....more concerned with comfort and function.
