I know this is about Yanmar panels and we have a Perkins, but I recently redid our engine controls as well.  Had to rewire the whole thing for the rats nest of mis-colored auto grade conductors.  Got the recessed panel from SSI Custom Plastics, the key switch and Faria gauges from ACDC Marine Inc.  Added a low press/high temp alarm and an LED idiot light just for kicks.  The re-wire was actually pretty straight forward, and there's many diagrams available online in addition to what came with the new instructions.  One of my pet peeves from previous owners is wires that go no where, or worse yet, are poorly spliced.  Took care of all that with the latest project.  Total cost with all the new wire, crimps, panel, gauges, switches, sending units, etc., was about $400-$450.  A good chunk of coin for a little peace of mind, but hey, it's totally doable if one is so inclined.  Here's a couple pictures of the before, and the after.

-Rich VanDusen
'77 T37 #91
svrambleon.com