Looking at buying a Garmin ECHOMAP 74cv to add a second unit at the bow just to run Panoptix, which I know it will do. The 74 of course has the off shore maps. I probably wouldn't ever use the mapping portion since it's already on my 73. But if I did want to add/change/convert the maps to the same as on the 73 is this an option.
Of course if anybody has a good 73 or 93 for sale cheap, I'm all ears.