If you have an NMEA2000 network, you can also use the Maretron harness, and then display all your
engine data on any MFD.
I do this (in addition to, not instead of the standard crappy gauges) and find it is really, really useful. I can display all the engine data in different places. Who spends much time at the
helm? I display it at my scuttle where it can be seen from anywhere in the
cockpit.
And I can display it at the nav table.
And you can set up alarms which will sound all over the network.
This is definitely the way to go if you have N2K and MFDs already -- all you need is the harness.
Maybe an excuse to go over to N2K if you haven't already.
Actisense also make one:
EMU-1 - Actisense EMU-1 Engine Monitoring Unit - NMEA 2000 for only $414.95 !
Probably cheaper and just as good.