I have an approximately 6-8 year old Minkota and Humminbird with Ipilot link.  Just upgraded my console unit to a Helix 9 and love it.  Would like to upgrade the front unit but am thinking I have to changeout the entire trolling motor system as well since the transducer is built into the head.  Am I correct?  Any thoughts/ideas?  If I do this is there value to what I am pulling out of the boat?