My ole 997 hummingbird is getting touchy. I am ready to upgrade. Looking at helix GN3 Si/Di. In order to educate myself better, will I need to replace my tru-hull skimmer puck for depth at high speed and get a new y cable? I was hoping it would be just a transducer and head unit changeout. Also are those skimmer pucks easy to remove after being glued for 6 years? Never removed one if I have too?