What you are talking about is called live imaging. Think of it as an actual picture (or video as it is) of what is going on under the water. The transducers are directional and can show you exactly how far away a fish is. It is so detailed sometimes you can actually determine species of fish on the screen. You can see it's tail, what direction it's swimming... and in live time. It's really incredible technology. You can go online and see comparisons of each live imaging technology and what it does. It's expensive so you really want to do your research to see if you absolutely have to have it. Where it excels in my opinion is more with still fishing/jigging then trolling, but it has advantages for everything. I'm a dyed in the wool Humminbird user and have been for many years, but if I am buying live imaging it's gonna be Garmin Panoptix for me. That's just an opinion, they are all good. Keep in mind any live imaging is a much bigger battery drain than anything you've used previously. Not really an issue for you as you are upgrading your batteries as well, but something to keep in mind.
And at the risk of sounding too much like a Garmin fan boy, I would seriously look at their offerings for trolling motors. I especially like how you don't have to change motors to go from 12v, 24v or 36v. Allows for upgradability without having to change the motor.
Between my 36v Minn Kota Ulterra and Helix 9's I have easily $5,000 invested in Johnson Outdoors products but if I had to do it again right now I would look heavily at the Garmin stuff.
