Finder Information Humminbird

[SkunkedAgain]

Wondering if anyone could help me with the differences between the Helix 7 Chirp, Mega SI, GPS, G3 and the Helix 7 Chirp, Mega SI, GPS, G3N?  I mean there is $175 difference in price, but is the networking capability that much more expensive, and if so what does it do for me?  I am planning on getting the Minn Kota (probably Terrova) and I really want to get good side finding capability, but I'm not rich enough to afford two finders in the same boat, so I'm doubting I'll have two finders networked between steering console and fishing position.  Is that what the networking means, or does networking have something to do with using the transducer on the Terrova and the Helix as the finder?  Guess I don't understand how those items play together.  I also need to decide if I need the I-pilot link or just the regular i-pilot?  Before I pull the trigger on the motor I want to make sure I get the one that is best for me and that I don't regret not spending the $200 more at the time, or maybe I should be thinking Ultrex or Ulterra, but I don't want to spend extra if I don't need the functions or won't use them... Just noticed the Terrova transducer doesn't support the mega SI, so maybe I'll have to upgrade the motor, so maybe I'm back to saving some more before I buy... Anyway would like to know your thoughts... Thanks Jeff