Can someone explain the differences between these 3? Always assumed the Magnum was just a standard TA, with a new name. These are all advertised as brand new units. I'm considering just replacing both TA units vs rebuilding them. These will be installed on a cruiser that is freshwater only, once put back in the water next spring, it will never come back out. Leaning towards using SS swivel pins, but concerned about the dissimilar metals.

Edit....
I found that the SeaCore units are the same as the regular drives, standard, mag, X, Xr's, etc, but they go thru an extra process. They get hard anodized, which coats the insides and outsides, plus all SS fasteners and better topcoating. These are geared towards saltwater use. Ca.nt find any info about freshwater use

The Seacore will be better in freshwater also. As far as the stainless pin, remember that the steel pin is dissimilar also. I would do the seacore in a heartbeat. No matter what you decide make sure your Mercathode controller is good and use a shore power isolator