What was the last generation of Lowrance unit to require the separate StructureScan Module (LSS1/LSS2) ? Do the Carbon or Live units require them or is everything built in to the unit/transducers now? I'm running Gen3's and looking to possibly upgrade to Carbons...need to know what to sell and what to keep? I see the Carbons advertised with SS-3D, is that built in or a separate module still? I want to gut my set up and start over. Thanks!