I have a new Sena Bluetooth which I love and I want to get GPS but I see no reason to spend hundreds on a stand alone unit. Does anyone recommend any of the iPhone navigation apps? I would like to multitask by listening to music and have the gps send the turn by turn voice commands. It would keep the phone in my pocket so I am less worried about 3d maps. Not sure if this can even be done but can't find anything on this.