I agree....external is best...although a pain. Pucks do go bad and if internal, you're hosed.

Yes, the navionics card should work in all unless you've got something really outdated....prolly ought to check with Navionics to make sure it's compatible before you budget on it though just to be sure.

I was doing some more thinking about your set up though....I'm recanting now that I see you'll end up with 2 GPSs.....Mount the SI at the back where your tiller is and you can see it and the GPS puck close to unit as possible....point being, repeatable position for accuracy.

Wannabe...