Chart plotters have come a long way - used to take two different C-Map cards to get from one end of LI Sound to the other. The plotter I bought last year (Lowrance HDS-5m) has the entire US on board - no chips needed (unless you don't like the Lowrance charts). Extra coverage? Takes any current Navionics card. Down side? Well, there's no way to update the installed charts - if the installed charts are out of date, the only option is to buy a Navionics chip (or a new plotter).
Recommend you review the current offerings in digital charts and decide what level of detail you need/desire? 3D, overhead photos, many options - what do you want? Then see which of your plotters works with the current charts.
I would not waste a lot of time looking for charts for an obsolete plotter.