I got a TomTom Rider 2 from a friend that is all there except the Blue tooth headset. What is the least expensive way of getting the audio on my bike? Can it be wired into the radio on my 2009 H-D Road Glide so it can come thru my speakers? Can I hard wire a earphone cord to my helmet or is the Scala Rider blue tooth my only (rather expensive) option? Thanks