I put a 12v 55lb Terrova on my boat back in August. Best upgrade yet. I run two batteries in series for the 12v, but could have just a easily put them in parallel and ran a 24v TM. I put my batteries in the small storage compartment under the front deck with a battery charger and used the original TM wiring to charge the cranking battery. A side benefit of this is that the boat is balanced better, especially when I moved the gas tank to the other side as well.
If you check out the Heritage owners page in Facebook, you will find many post, photos, and set-ups for the Terrova. Since the Terrova in much larger than the Edge, don't plan on using your original cover on the boat unless you put a quick disconnect on the TM so you can remove it when you put the cover on. There are also options for mounting as it won't fit in the same position as the Edge.
One other thing I learned is that the GPS puck should be close to the middle of the boat. I initially mounted mine on the bow but moved it to the side next to the shifting lever. Works better in iPilot anchor mode. I also found the universal sonar on the Terrova is very good and use it almost exclusively to fish from the bow. As a reminder, if you mount a Lowrance fishfinder on the bow, you will need an adapter cable to connect the sonar. I think the Terrova is set up for a Hummingbird FF, but my Lowrance Ti2 works just fine with the adapter cable.
Hope this info helps
