Here is some copy from a posting from a dealer on bbc about some of the G4 units released. The Apex units are a salt water version of the helix units I think and electronic of course is priced alittle higher.

#66Today, 07:40 PM
Ok so here’s the latest as of my meeting today. Helix units ship mid October with a nema 2k built in it. U will need to run the Humminbird Nema kit to link ur units as it’s part of the big plug on the back of the units. The Helix 15 has an additional button for saved screen selections.

Solix G3 has an updated processor in it and nema 2k built into it also.

Apex units seem to be a better and greater Ion series that will flush mount into bigger boats instead of having a raised surface. Expected first quarter of the year.

Now the last I have gotten is the new live mega stuff will be first quarter next year also. He did tell me it’s not gonna be more then a livescope and be able to run on Helix G3 8 units and up. Said it’s pretty sweet is really all I could get out of him.