It's not obsolete, but won't share a map card like gen 2 units wil, other than that it's just a little slower.
You can keep the five at the bow, and run it next to the ten networked or put it in the dash and runit with the 12, up to yu where you want more screens.
Do you have an lss-1 or 2 box currently? If so you can use it for the 10 up front and just get anther lss 2 for the rear, many don't like side on the troller, but some do, but it will give you down on the troller that way.
lots of options