I also have a Scala Rider but I have the Q2 which think it is a waste. It has bike to bike and FM which I think is a waste because if you leave the area you loose the FM channels and far as bike to bike don't need the distraction, just pull over. I think the Pro is a good choice. Far as GPS, I looked at the TomTom and read complaints about Tech Support was bad and some issues with product. I then went to Zumo 550 and at the time it cost me and arm, a leg and two fingers and a thumb but I love it. Now far as your GPS is concern you may think about an ( bluetooth audio adapter transmitter) to plug in to your GPS. They use to have a wiREVO D1000 dongle, but couldn't find one on the net, I must have bought the last ones. I found this one at Buy.com for about $20. I don't know anything about this one. But it is an option rather then buying a new GPS. I use a dongle on my GPS to listen to XM radio and I have no complaints.
Dan
http://www.buy.com/prod/bluetooth-3-5mm-a2dp-stereo-audio-hifi-dongle-adapter-transmitter-for/q/loc/111/213742315.html